Implemented game configuration settings feature (currently can adjust sound volume). Hooked up game settings to start screen. Improved start screen handling for buttons.

** Updated media resources: media_2014-03-31_18-32.zip
Tweaked start menu buttons. Added additional placeholder start menu buttons.
Updated big_castle map. Fixed bug where multiple enemy spawners on a map would conflict with each other. Modified spawn position for player units. Disabled automatic unit naming for enemy spawner.
Implemented basic suspend/resume game feature.