[mythtv] [experimental patch] pchdtv bttv support

[Daniel Thor Kristjansson]

   http://www.mrl.nyu.edu/~danielk/mythtv/daughtercard-v4.tbz

This patch adds support for recording on the bttv framegrabber on a 
pchdtv card. Most of the changes are in tv_rec.cpp, but there are also
minor changes throughout the code. The most significant change is that
I've added a lock on querying and setting the state in TVRec. This 
lock is taken also by RunTV whenever it is processing the events. I'm 
pretty sure I've got the locking right. But I'm using a monitored 
lock for now to help debug anything I may have missed. The monitored 
lock is implemented in monitoredlock.{cpp,h}, which you will need to 
copy to libs/libmythtv and add to the libmythtv.pro file. It can be 
replaced with a QMutex once I'm sure it's working correctly.

When a tuner is shared between two recorders the two recorders get one 
state lock to share between them. And when card one is being used the 
other cards using the same tuner are put into the new state 
kState_TunerIsBusy, which prevents the scheduler and users from using 
the card while it's tuner is being used by someone else.

There is a bug in the setup. If you are creating a new pcHDTV card in 
the setup program, you must edit it after you first create it for the 
bttv daughtercard settings to take.

This patch updates the database schema by adding a parentid column to 
the capturecard table, which means it also updates the db version.

Also this patch modifies the myth protocol so it updates the protocol 
version. So you will need to relink any plugins.

-- Daniel