[pxc] parameters for pxc

[Alessandro Rubini]

I've just committed all the changes I implemented in these days.
Now all parameters (brightness etc) are per-input, so switching the
input multiplexer restores the parameters for the other input.

Additionally, it will be possible (using pxc_param) to load parameters
dumped at a previous time. The program currently has only the "dump"
part implemented.

I'll fix the final details during next week and release 0.82. Meanwhile
I've made a CVS snapshot available, at
	ftp://ar.linux.it/pub/pxc/
and tomorrow from
	ftp://ftp.linux.it/pub/People/rubini/pxc/

This work has been sponsored by Michael Bianchi.

/alessandro