Move pure operations on class attributes into those classes

[mlevatich]

There's currently a lot of if character.alleg == C.Alleg.Hunter and if player.state != C.PlayerState.Dead kinds of things floating around, especially after #210

These sorts of checks on the attributes of characters, cards, etc belong in those classes, most of which are pretty empty at the moment. (for example, a Player.isAlive() function, or character.IsShadow()). This would do a lot to make the rest of the codebase more readable.

I'm not sure if there are any non-trivial operations that we can move in this way, but even moving the trivial ones still seems like a good idea to me.

[amritrau]

Strongly agreed on this one. I can try and handle this -- let's do this after we merge #208 and #210, though (we don't have enums in the main branch yet).