* 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

Seems like a typo, results in error:
TypeError: 'int' object is not iterable.

Fixing it:
for i in len(population) -> for i in range(len(population))

Style: delete excess parentheses. In some of these cases you need to read ahead to see that the paren is not introducing a tuple, for example.

* fixes an error in search.py

* modifies the method name 'exec' which is a built-in name

* modifies Fig. to Figure all over the repository

* fixed a small type in logic.py

* Change variable names from s_prime to s1, current_state to s1

* Sane default for update_state

* removes obsolete Fig dictionary from utils.py

* modified rl notebook according to the new Figure conventions

* removes 'import Fig' and changed the names of Figures

* fixes a small error (by me) in executing the cells in rl notebook

* Made Log Usage Consistent in text.py

* Added Explicit Imports from utils

* changes a typo of file name to /aima-data

* modified some documentaion and removed doc tests

* changed the names like Fig[2, 3] and added unit tests for search.py

* adds Fig[4.23] graph which is 1-dim state space problem

* adds LRTA star agent class

* adds fully implemented LRTA star agent

* adds tests for LRTA star agent

Apparently, set() does not equal {}

Problems fixed:
Replaced cmp: 1 instance in line 323 of search.py
Convert set() to {}: 3 instances in line 29 of MDP.py, line 181 and 215
of search.py
Convert .sort() to sorted(): 1 instance in line 150 of text.py
Cast map to list: 1 instance in line 47 of grid.py

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

Used tool 2to3 to finish the porting to Python 3 plus some fixes by
hand.

These functions, which I had to implement in Python 2.2, are now
available in standard Python.