* changed queue to set in AC3

Changed queue to set in AC3 (as in the pseudocode of the original algorithm) to reduce the number of consistency-check due to the redundancy of the same arcs in queue. For example, on the harder1 configuration of the Sudoku CSP the number consistency-check has been reduced from 40464 to 12562!

* re-added test commented by mistake

* added the mentioned AC4 algorithm for constraint propagation

AC3 algorithm has non-optimal worst case time-complexity O(cd^3 ), while AC4 algorithm runs in O(cd^2) worst case time

* added doctest in Sudoku for AC4 and and the possibility of choosing the constant propagation algorithm in mac inference

* removed useless doctest for AC4 in Sudoku because AC4's tests are already present in test_csp.py

* added map coloring SAT problems

* fixed typo errors and removed unnecessary brackets

* reformulated the map coloring problem

* Revert "reformulated the map coloring problem"

This reverts commit 20ab0e5afa238a0556e68f173b07ad32d0779d3b.

* Revert "fixed typo errors and removed unnecessary brackets"

This reverts commit f743146c43b28e0525b0f0b332faebc78c15946f.

* Revert "added map coloring SAT problems"

This reverts commit 9e0fa550e85081cf5b92fb6a3418384ab5a9fdfd.

* Revert "removed useless doctest for AC4 in Sudoku because AC4's tests are already present in test_csp.py"

This reverts commit b3cd24c511a82275f5b43c9f176396e6ba05f67e.

* Revert "added doctest in Sudoku for AC4 and and the possibility of choosing the constant propagation algorithm in mac inference"

This reverts commit 6986247481a05f1e558b93b2bf3cdae395f9c4ee.

* Revert "added the mentioned AC4 algorithm for constraint propagation"

This reverts commit 03551fbf2aa3980b915d4b6fefcbc70f24547b03.

* added map coloring SAT problem

* fixed build error

* Revert "added map coloring SAT problem"

This reverts commit 93af259e4811ddd775429f8a334111b9dd9e268c.

* Revert "fixed build error"

This reverts commit 6641c2c861728f3d43d3931ef201c6f7093cbc96.

* added map coloring SAT problem

* removed redundant parentheses

* added Viterbi algorithm

* added monkey & bananas planning problem

* simplified condition in search.py

* added tests for monkey & bananas planning problem

* removed monkey & bananas planning problem

* Revert "removed monkey & bananas planning problem"

This reverts commit 9d37ae0def15b9e058862cb465da13d2eb926968.

* Revert "added tests for monkey & bananas planning problem"

This reverts commit 24041e9a1a0ab936f7a2608e3662c8efec559382.

* Revert "simplified condition in search.py"

This reverts commit 6d229ce9bde5033802aca29ad3047f37ee6d870d.

* Revert "added monkey & bananas planning problem"

This reverts commit c74933a8905de7bb569bcaed7230930780560874.

* defined the PlanningProblem as a specialization of a search.Problem & fixed typo errors

* fixed doctest in logic.py

* fixed doctest for cascade_distribution

* added ForwardPlanner and tests

* added __lt__ implementation for Expr

* added more tests

* renamed forward planner

* Revert "renamed forward planner"

This reverts commit c4139e50e3a75a036607f4627717d70ad0919554.

* renamed forward planner class & added doc

* added backward planner and tests

* fixed mdp4e.py doctests

* removed ignore_delete_lists_heuristic flag

* fixed heuristic for forward and backward planners

* added SATPlan and tests

* fixed ignore delete lists heuristic in forward and backward planners

* fixed backward planner and added tests

* updated doc

* added nary csp definition and examples

* added CSPlan and tests

* fixed CSPlan

* added book's cryptarithmetic puzzle example

* fixed typo errors in test_csp

* fixed #1111

* added sortedcontainers to yml and doc to CSPlan

* added tests for n-ary csp

* fixed utils.extend

* updated test_probability.py

* converted static methods to functions

* added AC3b and AC4 with heuristic and tests

* added conflict-driven clause learning sat solver

* added tests for cdcl and heuristics

* fixed probability.py

* fixed import

* fixed kakuro

* added Martelli and Montanari rule-based unification algorithm

* removed duplicate standardize_variables

* renamed variables known as built-in functions

* fixed typos in learning.py

* renamed some files and fixed typos

* fixed typos

* fixed typos

* fixed tests

* removed unify_mm

* remove unnecessary brackets

* fixed tests

* moved utility functions to utils.py

* Added WumpusWorld testcases

Added:
 - Testcases in test_agents.py
Modified:
 - Duplicate walls are not added in corners now

* Tests for VacuumEnvironment and WumpusEnvironment

Added:
 - Test cases for Explorer actions in WumpusEnvironment
 - Test cases for VacuumEnvironment
Modified:
 - VacuumAgent correctly disables bump percept when agent sucks dirt after bumping into a wall

* Added spaces in tuples to comply with PEP8

* Reworked Introduction and 1-D environment in agents.py

Added:
 - Table of Contents and overview
 - A miniscule explanation of all required code from agents.py
Modified:
 - Some grammar and sentences
 - Structure of the notebook in 1-D environments to make it more coherent
Removed:
 - Outputs from notebook (Makes VCS tough and bugs tough to detect)

* Reworked agents in a 2D environment

Modified:
 - Removed global variable turn from 2D park model: Agent programs are not supposed to see anything except percepts
 - Bump percept is now generated when Dog is about to bump into a wall
 - Replaced all XYEnvironment with GraphicEnvironment - Gives better readability to both code and output (Previous way of just showing GraphicEnvironment in the end was redundant imo)
 - Restructured the 2D park and EnergeticBlindDog environment scenario to be more readable
Removed:
 - Redundant Park2D without graphics (subclass of XYEnvironment)

* Fixed issue #1030

Added:
 - ipython and ipythonblocks packages to requirements.txt

* Has some typographic improvements in agents.ipynb

* Added output to agents.ipynb

* Added notebook section for DTAgentProgram

* Updated README.md

* Minor

* Added TODO to fix pomdp tests

* Added notebook section on AC3

* Added doctests to agents.py

* Fixed pomdp tests

* Fixed a doctest

* Fixed pomdp test

* Added doctests for rl.py

* Fixed NameError in rl.py doctests

* Fixed NameError in rl.py doctests

* Minor fixes

* Minor fixes

* Fixed ImportErrors

* Fixed all doctests

* test commit

* agents.ipynb

* agents.ipynb

* Fixed all the instances of issue #833

* minor fix and cleared change in agents.ipynb

* Add test for TableDrivenVacuumAgent

* Debug Travis

* Minor fix

* Fixed table for TableDrivenAgent

* Update README

* Update agents.py

* Update test_agents.py

* Delete test_grid.py

* Delete grid.ipynb

* Delete grid.py

* Move grid functions to utils

* Move grid tests to utils

* Update agents.py

* Update mdp.py

* Update search.py

* Fix flake8 warnings

* Remove unnecessary #noqa

* Fix doctest

* replace assert with if test in add_thing

* removed inline assert

* added unit test to check edit

* improve user interface

* Exclude test files from flake8 check

* Fix flake8 for main files

* Add flake8 check to build

* Improved BlindDog example

* Added 2D GUI IPython capability

* Demonstrated 2D Environment with GUI

* allowing import without ipythonblocks installed

* added tests for Direction

* fixed Direction arithmetic error

* Update some comments

* Cleanup and remove some duplicate initialization

* Fix some comments quotation and little bugs: raising Exception instead of raising Failure, random.randrange(a,b) instead of random(a, b)

* Fix some comments quotation and remove explicit inheritance from object

* Fix 'r' in front of the ```parse_csv``` comments

* Fix quotation in comments

* Fix quotation in comments and fix bug in 'KB_AgentProgram'

* Update agents.py

* Update test_grid.py

* Update grid.py

* fix bold look on github's ipython view

* standardise docstrings

* Update search.py

Commenting issues fixed (spacing and punctuation was off sometimes).

* Update agents.py

* Update canvas.py

Grammar

* Update grid.py

* Update learning.py

Added period

* Update logic.py

Fix quoting

* Update mdp.py

Fixed quoting

* Update nlp.py

Capitalization and punctuation fixes

* Update planning.py

* Update probability.py

* Update rl.py

'th' to 'the'

* Update search.py

* Update text.py

* Update utils.py

* Update utils.py

* Update utils.py

* Update learning.py

Typo

* Update utils.py

* Replaced mean with standard lib function introduced in 3.4

* #TODO Replaced every with all

* Proper names for variables introduced in 2to3 conversion.

* modifies Fig. to Figure all over the repository

* fixed a small type in logic.py

* Made Log Usage Consistent in text.py

* Added Explicit Imports from utils

* Model for ContinuousWorld

* Added PolygonObstacle Class

* Added HTML for Continuos World

* Added JS for Continuous World

* Implemented ContinuousWorldView Class

Implemented arrow shooting in Wumpus World. Wumpus Environment is now complete.

Fixed bug where dead agents still get to act (Environment)
Improved Direction class to ease 2D Movements (Direction)
Implemented an easier way to iterate with and without walls (XYEnvironment)
Added is_inbounds() method to check if location is within the width and height. Works within walls also. (XYEnvironment)
Multiple Minor Fixes(agents.py)

WumpusEnvironment

- Fix relative imports in base of is a package or not
- Fix not working notebooks
- Add notebooks to packages sources