syncing changes from ssc svn, mostly.

[Course.cpp] HasTimedMods() now actually checks for timed mods (technically non-global) instead of being a clone of HasMods()
[Player.cpp] add MAX_HOLD_LIFE/[Player] MaxHoldLife metric
[ScreenGameplay] looking into places to put loading of replay data, perhaps?
[elsewhere] lots of cleanup, and I'm sure there's lots more to be done.
add a todo to ProductivityHelpers.

src/PlayerAI.cpp

@@ -75,6 +75,7 @@ TapNoteScore PlayerAI::GetTapNoteScore( const PlayerState* pPlayerState )
 		return TNS_W1;
 
 	/*
+	// handle replay data playback -aj
 	if( pPlayerState->m_PlayerController == PC_REPLAY )
 	{
 		// ghost house