A general GameScreen implementation, Pt 2

Previously, I posted an implementation of Eli's GameScreen design that I'm using for the games in my book. I've just added two new virtual functions to the GameScreen class - BeginPause and EndPause. I did this to make dealing with audio easier - when a screen is about to lose updates, it should mute it's sounds, and then it can unmute them when updates resume. The change isn't terribly complicated, and it passes the smoke test, so I thought I'd post it for folks to use. GameScreen1.1.zip P.S. Last night, someone asked me if I was planning to change this class, and I swore I wasn't. I forgot about this feature. Sorry.