Made texture use the framebuffer color ordering

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Improved numeric stabillity of rasterizer

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Updated README file

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>