First steps with the V9990

I modified the UBox library of Juan J. Martinez to get it working on the V9990. This video gives a short impression of the first results, just a simple game to see how things work out and some placeholder music.
Current version supports most of the existing function calls, with addition of palette functions (including fade) and layer functions on screen mode P1 and P2. Next to that the sprite manager can handle the full multicolor sprites of the V9990.