[mythtv] [patch] TVRec exit removal

[Daniel Thor Kristjansson]

This is a resubmit of the TVRec exit removal patch.
I went back and made sure all the lines were less than 80 columns
and all the "if" statements had a return before the open brace "{".

I've also removed one new exit() call for FireWire. This is similar
to the tv_play exit cleanup patch in that it moves all initialization 
that can fail to the Init() function, and returns false if the 
initialization fails.

The goal is to remove all exit calls from the libraries. These 
particular exit calls are not very distressing, but it's nice to be able 
to just run "grep exit\( libs/libmythtv/*.cpp | grep -v _exit"
and see no output.

Actually, there are still some problem areas:
libs/libmythtv/RingBuffer.cpp:        exit(-10);
libs/libmythtv/osdlistbtntype.cpp:        exit(-16);
libs/libmythtv/proglist.cpp:                exit(-17);

But, I'll get to these...

-- Daniel