Fixed TerrainIndex problem: needed to make a new addingThisTerrain each time you run the loop, or it'll just put the same Terrain object down for the entire map. Also fixed 2D array declaration syntax in MovableGameMember, moved/renamed property in Terrain to better match existing style, and added a couple requests for comments in the Level class.

And. . .sorry for the large commit & commit comment. I'll try to be a little less verbose in the future.