Version 1.2: Redraw only necessary screen elements
Refactored mvcView, per Raymond Chen's advice in The Old New Thing, to trust WM_PAINT. So we refactored the entire drawing engine. Specifically, when we detect changes to the model (DTMF tones are turning on or off) we now invalidate that region of the screen. Then, we wait for WM_PAINT to run. This moved the entire screen redraw off of the Audio Capture Thread and to WndProc's message loop. This, in turn, reduced the number of DATA_DISCONTINUITY in Release mode to 1 (the initial audio packet).