Initial Commit.
Reorganized some methods to group them categorically. Added some missing documentation.
Added class-level documentation. Organized default TerrainBehavior conceptually.
Added a bounds checking method to ImmutablePoint and the associated tests in ImmutablePointTest
Refactored Map and Tile to use ImmutablePoint.inBounds(). Added documentation to Tile.
Organized Imports.
Added documentation for Terrain and DefaultTerrain. Corrected typos.
Added last name to @author to reduce ambiguity.