reindent.
start to split the giant pseudoheader into per-library smaller ones.
we need swscale2.
amend previous stale commit.
Fixed a typo
move decls in the correct pseudoheader, add a new needed one.
enter the Image class, spawned from video.Frame.

The Image class will allow the client code to access the real Picture data,
while the video.Frame class will still holds all the extra data which
allow a Picture to fit into a (video) Stream.

an Image provides also a conversion routine to have a new copy of the
same data (of course in a new Image object) but with a different colorspace.

More conversion helpers will follow in the future if need arises.

Samples, the correspinding from audio.Frame, will follow soon.

...And also better super() usage. (Yeah, this is a erroneously stashed
commit. My bad.)

--HG--
extra : amend_source : 0ffcfcfa7b886fda9b7e5fc60168bc53fde62888
Remerge.
better repr
more robust pseudoheader loading.

There are still some rough edges, still. The correct dependencies
between pseudoheaders aren't enforced and nowadays the thing works
by pure luck (!!!). Needs love ASAP.
credit goes where credit is due.
Pull from HG.