[mythtv-cmyth ]Remove 'failed to connect to mythtv backend' notification

Currently if the addon is unable to connect to a previously working backend
(because backend is suspended or unreachable via network) it displays a pop up
every 10 or so seconds, which appears in all menus and over video/visualizations
and plays a notification sound.
[cmyth] Improve separator checking in cmyth_rcv_string

This improves the checking for string separators []:[].
In case a string ends with a part of a separator, the
code did not find the correct separator.

It was reported by a user that a recording "Title ["
breaks the loading of recordings because it does not
recognize the string's end. The protocol showed
"...[]:[]Title[[]:[]Subtitle...", and cmyth_rcv_string
returned "Title[[]:[]Subtitle".
[mythtv-cmyth] Revert TCP_RCV_BUF_DATA_SIZE to prevent stuttering

A value of 128000 causes stuttering on linux x68_64.
Reverting to the original value of 65536.
sync ffmpeg codec ids. closes #195
[mythtv-cmyth] Start development v1.7.12
[cmyth] Connect Playback or Monitor

- New functions to connect as Monitor or Playback to the backend
[mythtv-cmyth] Connect Playback or Monitor

Add 'playback' flag to the initializer of MythConnection and select annoucement type.
- Recording stream control connection use Playback annoucement to prevent backend shutdown.
- Addon control connection use Monitor annoucement to allow backend shutdown.
[cmyth] Add cmyth_mysql_get_prog_finder_chan

Function allows to find the current program on the given channel.

Thanks to Aubrien for the patch.
[mythtv-cmyth] Set start/end time for instant recordings correctly

Add FindCurrentProgram to find the currently active program on a given
channel. When adding a instant recording, set the correct start/end time
from this program.

Thanks to Aubrien for the patch.
Merge remote-tracking branch 'upstream/master'
[mythtv-cmyth] Fix stopping Live TV

This fixes stopping of Live TV by returning 0 in ReadLiveStream.
Stopping Live TV is currently used for the conflict handling.