New port: pvrxxx for Hauppauge PVR150/500

[Dieter]

> That would allow people to run a KnoppMyth / Linux-based MythTV backend
> server and Mythfrontend on FreeBSD machine(s) until we have good enough
> TV card drivers under FreeBSD.

The first thing we need is good tuner support in BSD.  Nothing against the
Hauppauge PVR150/500 cards, but IIRC they are analog-only cards.  Analog
broadcasts are going away soon, so we need support for DIGITAL tuners.

The second thing we need is video output support, including at least XvMC.

MythTV is 3rd priority at most.