x264 Video Codec r996

The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit(OS X), Min Chen (vfw/asm), Justin Clay(vfw), M�ns Rullg�rd, Christian Heine (asm), and Alex Izvorski (asm).
Note: x264 is still considered alpha, so errors can (and will) occur!

Main features:
- CAVLC/CABAC
- Multi-references
- Intra: all macroblock types (16x16, 8x8, and 4x4 with all predictions)
- Inter P: all partitions (from 16x16 down to 4x4)
- Inter B: partitions from 16x16 down to 8x8 (including skip/direct)
- Ratecontrol: optional VBV, single or multipass ABR, constant quantizer
- Scene cut detection
- Adaptive B-frame placement
- B-frames as references / arbitrary frame order
- 8x8 and 4x4 adaptive spatial transform
- Lossless mode
- Custom quantization matrices
- Parallel encoding of multiple slices
- Interlacing

Enhancements:
- Check whether echo -n works, otherwise try printf (fixes build on current OS X 10.5)