RandAI makes illegal plays

[mgaree]

Sometime after my refactoring of cards.py, RandAI has gained the ability to make illegal plays.

[mgaree]

In checking play legality in AIBase, numbers were being checked for equality using is instead of ==. The function was copied from game.py where is was also used. While is is lovely and pythonic, it is wrong. See here: http://stackoverflow.com/a/133024

After the refactoring of cards.py, ranks and suits are showing up as floats instead of ints. So the fact everything worked before refactoring was due to an unusual implementation (caching) in Python, not because it was the correct thing to do.

I changed is to == as appropriate in some other places, but not everywhere.

[mrpoodlepants]

:(