avcodec: map KGV1 (Kega Game Video)

Sample:
http://samples.mplayerhq.hu/V-codecs/kgv1/kgv1.avi

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
avcodec: map Canopus Lossless (CLLC)

Sample:
http://fate-suite.libav.org/cllc/sample-cllc-rgb.avi

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
avcodec: map Auravision AURA

Sample:
http://fate-suite.libav.org/auravision/SOUVIDEO.AVI

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Add .thp extension
Add .txd extension

But do not register it by default on Windows.
Add .rpl extension