beos/mov/adpcm patch by François Revol <revol at free dot fr>

* Some BeOS fixes:
- errno stuff
- nanosleep() replacement
- added a doc/README.beos

* mov reader still has problems with most videos (skips many chunks),
- It should now read .mov files with zlib-compressed moov headers (aka cmov)
- added SVQ1 support.
- removed mapping 'raw ' and 'yuv2' to h263, was my mistake.
- added IMA4 support. (tested)
- fixed frame rate (it reported 0 fps or something before)
- extended file probing ('wide' and 'free' atoms)
- improved .mov/.mp4 detection (or so I think)

* adpcm
* added zlib support, with header file and lib check

Originally committed as revision 780 to svn://svn.ffmpeg.org/ffmpeg/trunk