-Fix[FS#1519]: When you can not use this resolution at full screen, now you'll know that it failed.
As for the reason it did not work, each computer/OS has its reason.
-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
-Add: added NULL blitter and renderer, which are always used for -vnull
-Add: dedicated driver doesn't blit nor render by default. Can be overruled by user. (-D -b 8bpp-optimized)
-Remove: removed CTRL+D from win32, which is incompatible with above
-Add: extended screenshot support for PNG and BMP
-Codechange: remove all hardcoded 8bpp references and replace them with more dynamic ones
-Codechange: minor stuff in blitters