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/ScreenGameplay.h

@@ -177,6 +177,7 @@ protected:
 	virtual void SaveStats();
 	virtual void StageFinished( bool bBackedOut );
 	void SaveReplay();
+	//bool LoadReplay();
 	bool AllAreFailing();
 
 	virtual void InitSongQueues();