Moved backgrounds into "Backgrounds" assets folder. Any BGAnimation may be used now.

Cleaned up many, many graphics.

stepmania/src/ScreenSelectStyle.cpp

@@ -88,7 +88,7 @@ ScreenSelectStyle::ScreenSelectStyle()
 
 
 	m_Menu.Load( 	
-		THEME->GetPathTo("Graphics","select style background"), 
+		THEME->GetPathTo("BGAnimations","select style"), 
 		THEME->GetPathTo("Graphics","select style top edge"),
 		HELP_TEXT, false, true, TIMER_SECONDS
 		);