Cleaning up documentation and code file by file.  Progress towards issues #27 and #28.

Added JSDoc style documentation comments.

Actually did get rid of game.onStart().  Better to add it back in if/when it gets used.

Deleted game.getCurrentRoom(), as nothing was referencing it and it duplicates game.currentRoom.

Cleaned up argument names in game.registerConnection.

Removed unused add/remove Item functions.