[mythtv] Exclusive access to the cutlist editor

[Jim Stichnoth]

I noticed a problem in the cutlist editor.  When you start editing, it
first checks whether the editing column of the recorded table is set
(ProgramInfo::QueryIsEditing()).  If so, it is supposed to bring up a
dialog prompting you whether to continue editing or not.  The problem
is that this dialog is not coming up for some reason.  Instead,
playback is simply paused.  This is easily reproduced by entering the
editor, forcibly restarting the frontend, and then reentering the
editor on the same recording.

I wanted to ask whether anyone else is seeing this before filing a bug
or digging into it.  More importantly, though, I also want to ask
whether people think this "editing" column really has value.  My
opinion is that it should be removed.  It feels like there were good
intentions when it was introduced, but today it strikes me as an
incomplete solution to a not very important problem.

Jim