efa81bc: don't filter NoteSkins at a PrefsManager/NoteSkinManager level. Leave the NoteSkin sorting and filtering up to the theme. [Chris Danford]

ScreenWithMenuElements.cpp - add Cancel command, so actors can react to Cancel.
GameState.cpp - cleanup

src/GameState.cpp

@@ -741,7 +741,6 @@ void GameState::FinishStage()
 {
 	// Increment the stage counter.
 	const int iOldStageIndex = m_iCurrentStageIndex;
-
 	++m_iCurrentStageIndex;
 
 	m_iNumStagesOfThisSong = 0;