Update metadata of recorded programs when adjusting recording schedules

[Robert Tsai <rtsai1111>]

The patch for #171 added support for a new "AutoExpire by Priority" policy.

This patch adds code such that when priorities are adjusted in the "Set Priorities" UI, priorities of already-recorded shows are also changed to match that of their parent schedule, so that auto-expire-by-priority reflects the priorities in the "Set Priorities" UI. One-time recordings are still "orphaned", though (e.g., no frontend UI to change their recpriority/autoexpire priority).

[cpinkham]

(In [7234]) Patch by Robert Tsai to update recpriority on recorded programs when the recpriority on the Scheduled Recording for that program is changed. References #171, Closes #311.

[Robert Tsai <rtsai1111>]

A forthcoming patch moves the "UPDATE recorded SET recpriority" query out of ProgramInfo::ApplyRecordRecPriorityChange and down into ScheduledRecording::save where it really belongs, so that anything modifying a recording schedule (either the "Set Priorities" screen, or the "Edit Recording Schedule" screen, or any new screens) will also update selected fields of the "recorded" table. The "selected fields" are:

• recpriority
• recgroup
• transcoder
• timestretch

These were selected simply by what I thought would be intuitive (the only ones I really care about are recpriority and transcoder). Other fields that might be possibly updated, but aren't:

• autoexpire (I left that alone since the UI allows people to toggle the auto-expire flag on a per-recording basis)

[cpinkham]

(In [7756]) Apply the rest of Robert Tsai's "Update metadata of recorded programs when adjusting recording schedules" patch. This updates the recpriority, recgroup, transcoder, and timestretch values on recorded programs when their corresponding scheduled recording entry is updated.

References #171, Closes #311.