-Codechange: added CopyImageToBuffer, which produces a readable buffer for screenshots
-Fix: 32bpp-anim now holds animation on transparent objects to avoid strange graphical effects
-Fix: 32bpp-anim now works correct on mouse-movement (it holds the palette animation correctly)
-Codechange: introduced a hierachy of blitters to avoid a lot of code duplication
Note: this allows much easier adding other types of video-drivers, like OpenGL