0024644: Draw_Printer - provide the way to control messages gravity filter

0024644: Draw_Printer - provide the way to control messages gravity filter

Message_Printer - define GetTraceLevel()/SetTraceLevel() methods in base interface.
Implement message gravity filter in Draw_Printer.
Add new Draw Harness command dtracelevel to show/change message gravity filter.
Redirect default messenger to Draw_Printer within TKDraw instead of TKXSDRAW

Draw::Commands() - assign Draw_Printer only once