Add codec tags for the formats:
[15]BGR Packed RGB 5:5:5, 16bpp, (msb)1A 5R 5G 5B(lsb), big-endian [NOT in AVI]
[15]RGB Packed BGR 5:5:5, 16bpp, (msb)1A 5B 5G 5R(lsb), big-endian [NOT in AVI]
[16]BGR Packed RGB 5:6:5, 16bpp, (msb)   5R 6G 5B(lsb), big-endian [NOT in AVI]
[16]RGB Packed BGR 5:6:5, 16bpp, (msb)   5B 6G 5R(lsb), big-endian [NOT in AVI]
RGBA    Packed RGBA 8:8:8:8, 32bpp, RGBA [NOT in AVI]
BGRA    Packed RGBA 8:8:8:8, 32bpp, BGRA [NOT in AVI]
ABGR    Packed RGBA 8:8:8:8, 32bpp, ABGR [NOT in AVI]
ARGB    Packed RGBA 8:8:8:8, 32bpp, ARGB [NOT in AVI]
RGB[24] Packed RGB 8:8:8, 24bpp RGB [NOT in AVI]
BGR[24] Packed RGB 8:8:8, 24bpp BGR [NOT in AVI]

which are listed in the nut4cc.txt spec.

Originally committed as revision 23074 to svn://svn.ffmpeg.org/ffmpeg/trunk