LR-99: Battle Engine v1

Nevermind I figured it out. Implemented `REGIONAL_MONSTER_DISTRIBUTION` as follows:
>REGIONAL_MONSTER_DISTRIBUTION = {RegionType.ERIADOR : {Nazgul: [0, 1]},
RegionType.BARROW_DOWNS : {Troll: [0, .3], Goblin: [.3, 1]}}

These are used as the endpoints of distributions.