Major update - Fixed H264 header info, PTS timing, option to remove subtitles...

Hi Dickon,

This is a major update so I will understand if you don't want to pull as is, but take inspiration from it.

I've rewritten the openmax setup and basically broken it down into more understandable chunks, I've also removed the sleeps and replaced them with a message passing system to wait for confirmation on commands.

Added to that I've fixed the problem of the H264 header info not being in the proper place in the file for mp4 and mkv files. I've also rebased the PTS timestamps to ensure that mkv files now show the proper duration.

Finally I've added an option to remove subtitles (I've got a lot of recordings that contain DVB subtitles that don't fit into the common container formats).

Oh and the bit that I now tends to be a hot topic I converted the tabs to spaces, sorry :-)

My raspberrypi has now churned through ~440GB of  MPEG2 transport stream recordings without issue.

Cheers

Adam