Update ViewerTest and VoxelDemo to not use UserDraw callbacks.
OpenGl_View::blitBuffers() - set 0 GLSL program after blit
to avoid side effects on code that does not use shaders.
Drop interfaces Aspect_GraphicCallbackProc, Graphic3d_CUserDraw,
Graphic3d_Group::UserDraw(), OpenGl_GraphicDriver::UserDrawCallback().
V3d_View::SetWindow() - remove optional arguments initializing redraw callback.
OpenGl_View, declare following methods as virtual for inheritance:
redraw(), redrawImmediate(), render(), renderScene(), drawBackground(), renderStructs().
VocelClient_VisDrawer - do not include removed header
Removal of VoxelClient
VoxelDemo sample is redesigned so that it doesn't require compilation of OpenGl classes. It refers to TKOpenGl.dll as to an external library.
Some minor bugs are fixed in OCAF and Viewer 3d standard MFC samples