Enums for TapNoteType, TapNoteSubType, and TapNoteSource

I intend to make additional useful information available on judgments,
such as TapNoteType and TapNoteSubType( for hold judgments ).

I am submitting this part as a separate pull request because it is more
generally applicable to anything TapNote related.

src/GameSoundManager.cpp

@@ -657,7 +657,7 @@ void GameSoundManager::Update( float fDeltaTime )
 			// Otherwise, for each index we crossed since the last update:
 			FOREACH_NONEMPTY_ROW_IN_TRACK_RANGE( lights, cl, r, iRowLastCrossed+1, iSongRow+1 )
 			{
-				if( lights.GetTapNote( cl, r ).type != TapNote::empty )
+				if( lights.GetTapNote( cl, r ).type != TapNoteType_Empty )
 				{
 					LIGHTSMAN->BlinkCabinetLight( cl );
 					break;