Rockbox

Here is my first stab at color BMP support in Rockbox.

The read_bmp_file() function can now load both
monochrome and (24-bit) color BMP's. You can select
which format the BMP shall be stored in, either
FORMAT_MONO, FORMAT_NATIVE or FORMAT_ANY.

The read_bmp_file() function populates a bitmap struct
with the width, height, data pointer and the format, so
the application can select the proper lcd_bitmap
function to draw it.

The WPS is updated to make use of this and can now show
both monochrome and color BMP's.

Known issues:

1) Only 24-bit color BMP's supported yet

2) The rwps crashes if it tries to display a color BMP.
This is because the rwps shares images with the wps,
but doesn't know the bit depth of the attached screen.

Check it out and give me comments.