COMPRESSION CHANGES:
- Added prediction range and quantization threshold params (phy, phq, etc...)
  for compression control.
- Fixed error in quantization table upload function that was causing compression
  to not work.
- Decompression code cleaned up somewhat.

/proc CHANGES:
- /proc info file now reports actual picture settings (brightness, etc...).
- /proc/video/ov511/video<minor#> renamed to /proc/video/ov511/<minor#>/info.
- Added /proc/video/ov511/<minor#>/button, for checking snapshot status.
- Using create_proc_read_entry() instead of deprecated create_proc_entry()
- ov511.h: Added proc_devdir, proc_info, proc_button, proc_control to usb_ov511.

OV518 CHANGES:
- Added prelininary OV518 Start-Of-Frame and End-Of-Frame detection.

OTHER CHANGES:
- Added ov51x_clear_snapshot() and ov51x_clear_snapshot().
- Initial OV511 regvals were not setting up snapshot properly.
- ov511.txt: Minor updates