Replace bools with enums where appropriate

[tomassedovic]

Things like setting fullscreen/windowed mode or whether path.walk should recalculate or not should use aptly-named enums instead of an opaque boolean that you have to dig into docs to figure out.

[jgilchrist]

Is it possible that we could also replace the bitflags with enums? Most of them are just mutually exclusive settings anyway (we'd need to keep them internally to pass through to tcod-sys but it's a good opportunity to provide a nicer interface).

[tomassedovic]

I tried to use enums where the values were exclusive and bitflags where you could genuinely specify multiple options at once.

But yeah, I may have missed something and it's quite possible that we can design a better API for the bitflags cases, too.