CHANGES:
--------
5/12/99:
	- Clean up of open() code.
	- Restructuring common code for adding vbi support.
	- Added read() support.
	- No vbi yet...
22/11/99:
	- Complete restructure thanks to Kyosti Malkki
	- Preliminary tuner AFC support
	- Clipmap cleanups
	- Support for partially off-screen images
12/09/99:
	- Brought card types up to date with bttv0.6.4f
	- Improved RISC engine reliability with poor sync
	- Speeded up clipping code dramatically (now seems faster than stock
	  bttv)
	- Added support for multi-field capture
	- Security fixes
	- Tighter v4l2 compliance
