Takes two or more bitmaps and remaps their colors so that their colors will be aligned after eachother. This allows sprites to be faded separately. The limitation is that the bitmaps can't have more than 256-start_color colors in total.
bitmaps is a sequence of two or more bitmaps.
palette is the palette you want to modify.
start_color is the color where the mapping starts. The first color of the first bitmap will be remapped to start_color.