Added a message window and game messages

Added a game start message to game.coffee
Added a messages field to GameState
Added code to the gui to display messages in a message window
Modified gui code that displays weapons and ammo status
Modified Player to add a lot of game messages
- Out of stamina and attempting to run
- Messages for each item pickup
- Messages for hitting, missing, and breaking the bat
- Messages for trying to use a pistol or shotgun we don't have
Modified Zombie to add game messages
- Attacks that hit and miss
- An end of game scream death