Bug report: http://code.opencv.org/issues/3329

create `d_fgimg` matrix before cleaning.

"#error" requires DOS line endings (or fails with fatal error C1004: unexpected end-of-file found)
See: http://connect.microsoft.com/VisualStudio/feedback/details/794991/c-error-directive-and-unix-line-endings-leads-to-an-unexpected-end-of-file
So replace them to #pragma message.

This will allow to disable modules between cmake runs

we doesn't create OpenGL windows by default
OpenGL window must be created by user via namedWindow