SECURITY FIXES:
- Structures allocated in ov511_ioctl() are cleared before use
- Frame index passed to VIDIOSYNC was not being checked for validity before use

OTHER BUG FIXES:
- Handling of sensor register 12h improved
- All references to OV518+ changed to OV518
- ov511_move_data was using a hardcoded value instead of FRAMES_PER_DESC
- Fixed assumptions in VIDIOCGMBUF and VIDIOCMCAPTURE that OV511_NUMFRAMES == 2
- OV511IOC_GINTVER was accidentally not implemented
- Was using OV6xx0 slave IDs when I meant to use OV8xx0 slave IDs
- ov511.h: Removed prototypes for functions that no longer exist

VISIBLE CHANGES:
- Decompression code moved from ov511.c to ov511_decomp.c
- Compression always enabled with ov518 (it doesn't have an uncompressed mode)
- ov511.txt: Updated

INTERNAL CHANGES:
- Removed ENABLE_OV511_COMPRESSION option
- Added global variables for decompression options vectors
- Added ov51x_mmx_available global variable
- usb.h include moved to ov511.h
- ALLOCATE() and FREE() macros moved to ov511.h
- All references to OV518+ changed to OV518
- Sensor window setup code moved to ov51x_set_sensor_window()
- ov51x_request_decompressor() and ov51x_release_decompressor() added
- ov518 image parsing moved to it own function (ov518_move_data())
- Added ov511_register_decomp_module() and ov511_deregister_decomp_module()
- ov511.h: Added raw frame format enumeration
- ov511.h: Moved compression-related variables to top of struct ov511_frame
- ov511.h: Added struct ov51x_decomp_ops