Rewrite to use video4linux2 API.

Rewrite to use video4linux2 API.

- Add "-q" (quiet) and "-T" (tuner) options to fmscan.

- Improve fmscan frequency calculations.  It should now be better at
  accurately finding radio stations.

- Add Autotest test suite and, in the process, convert the packaging
  to use Autoconf and Automake.

- Some code and some documentation used a range of 0-65535 for volume,
  other code and other documentation used a range of 0-100.  This has
  been consistently changed to 0-100.