* Added tests for information_content

Added some tests for information_content function from learning.py

* Added test for information_content

* Update learning.py

* Update test_learning.py

* Modified table for TableDrivenVacuumAgent

* Add learing agent

* Add image for learning agent

* Add test for TableDrivenVacuumAgent

* Debug Travis

* Minor fix

* Fixed table for TableDrivenAgent

* Update README

* Fixed reset function to reset placeholder variables as well

* Added functionality to display best policy

* Enhanced explanation of value iteration

* Fixed minor typo

* Fix EightPuzzle class implementation

* Fix EightPuzzle class implementation (#710)

* Address style issues (#710)

* Added Policy Iteration section

* Removed ambiguous test

* Capitalized header

* Added images

* Added section for sequential decision problems

* added overview for AdaBoost

* added implementation for AdaBoost

* added example for AdaBoost

* added tests for AdaBoost

* rephrased sentences

* final changes to AdaBoost

* changed adaboost tests to use grade_learner

* grammar check

* Add SimpleProblemSolvingAgent

* Fix typo in search.py

* Added vacuum_world.ipynb

* Add psource for environment

* added submodule

* fixed ac3 in csp.py

* added a test to verify the modified ac3 algorithm in csp.py

* Update .gitmodules

* Added GridMDP editor to create and solve grid-world problems

* Added reference to grid_mdp.py in mdp.ipynb

* Replacing %psource with psource function

* Print matrix to console as well

* added submodule

* removed duplicates

* minor changes

* Update README.md

* removed an unwanted commit

* Added dropdown option to solve using genetic algorithm

* Added option to solve using Hill Climbing

* Added messagebox to confirm exit

* added Best First search

* fixed minor conflicts

* minor changes

* Added explanation of Genetic Algorithm functions using an example

* Added GUI version of genetic algorithm example (phrase generation problem)

* rebase with master

* solve error

* solve error

* solve error

* Update search.ipynb

Add features like selecting cities to be part of tsp, controlling temperature and speed of
animation.

* Update PeakFindingProblem code to allow diagonal motion

* Fix unit test issues

* update PeakFindingProblem to take actions as input param

* Refactor code in search.py

* Added Vacuum Agent

* Minor Fix

* Improved Font

* Added XYVacuumEnv

* Minor Fix

* Review changes

* added example for Decision Tree Learner

* fixed docstring in learning.py and description in learning.ipynb

Partially solves #687