Blt background, Raster operation Blt sprites

This test draws a background consisting of gradients, and then draws three objects using three different common Win32 raster operations, specifically SRCCOPY, DSTINVERT, and PATCOPY. The SRCCOPY should be a color palette, the DSTINVERT should invert the background, and the PATCOPY should show a pattern revealed under the object (the object moves, the pattern doesn’t).