Started writing the Combatant logic

I already have a lot of plans for how the Combatants, or the characters that
fight each other in the game, will be designed. In this commit, I started
working on them. I realized that I still have a lot more foundational code I
need to write in order to make sure the architecture I have designed is solid,
though. This code will likely influence my decisions about how Combatants are
designed, so it needs to be finished first. So I'm throwing this commit in
a separate branch so I don't lose my progress, but freeing me to work on the
higher-priority code first.
Skeleton code for skit component

Like how the previous code introduced code to hint at the architecture of the
battle component, this commit introduces code that provides the architecture for
the skit, or cutscene, component.
Merge branch 'combatant'

I'm done writing the basic architectural code and am ready to start programming
the core game logic!
Combatant Stats class

Wrote the Stats class, a POCO that keeps track of the RPG-style stats for
Combatants in a battle.