* 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

* Implementing HITS algorithm

* Moving HITS work to nlp.py and test_nlp.py

* 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

- 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.

Fixed error in Chart parses method, where it would
incorrectly return some parses that did not start at the beginning
of the input (and therefore did not span the whole input).