rewind changes in three game states, #44
change TransitionGameState to LoadingScreen, #44
add method LoadingScreen::enable() and fix parameter bugs, #44
refactor loading screen of StateStartup, #44
remove pragmas for unused parameters
remove comments, #44
refactor loading screen of StateLoadGameContent, #44
fix bug in LoadingScreen, #44
update StateLoadGameContent
refactor loading screen of StateUnloadGameContent, #44
fix bug in LoadingScreen, like described in #44
refactor LoadingScreen, #44
Merge pull request #45 from dixx/issue44

Closes #44