Enable more ffmpeg logging at startup of playback.

Allow logging in avformat_find_stream_info() if
"-v libav --loglevel debug" is specified.
This proves useful for live TV debugging among others.
Remove the Delete Recordings screen.

This screen was nearly functionally identical to the Watch Recordings
screen.  The primary differences between the two were the default
sorting order and whether the default SELECT action deleted or played
the currently selected recording.  The one, small, hard-coded feature
of Delete Recording to display the total disk space used by a group
has been added to Watch Recordings.  The remaining difference is the
displayed information and that is controlled by the theme.  Of the
included themes, only MythCenter-wide had specail support for Delete
Recordings.  For it, the total disk usage bar-graph has been added to
Watch Recordings.
Fix Live TV startup, particularly for analog PVR-xxx tuners.

At the start of playback, ffmpeg scans the start of the file for
stream info.  While reading packets, it uses ffio_limit() to truncate
packets during attempts to read past the size of the file.  The file
size is cached at the start of playback, and may be inordinately small
for live TV files, triggering a storm of packet truncation and failure
to start playback.  We fix this by faking a large file size for live
TV playback during the initial call to avformat_find_stream_info().
Delete a couple more remnants of the Delete Recordings screen.
Fix StatusBox to account for template recording rules.