Do not display background shape in fullscreen notification if there’s nothing in it

So nothing cover a photo when using AirPlay photo sharing

(cherry picked from commit 92f02ac76c7011420b3e2981210826f651dc65da)
Improve AirPlay device visibility in iOS 7

For some reasons, my iPhone doesn’t always show mythtv as an AirPlay device, and more often than not only show it as an audio device.
After playing a lot with the various bonjour advertising data, what I can gather is:
- If AirPlay video reports a version >= 120.x; the iPhone will attempt to use FairPlay DRM no matter what RAOP reports (even if it reports no support for encryption)
- If there’s a mismatch of version between AirPlay video and RAOP: the iPhone 5 won’t show the video service
- If reporting a version < 110 in AirPlay video, then photo sharing doesn’t reliably work
- If bit 10 in features bitmask is cleared, it doesn’t reliably show up
So I set the AirPlay video version to 115.3 (made up value) that allows photo sharing, and RAOP also to 115.3 and it all seem to work nicely now

(cherry picked from commit 7e2f21c8a3614fe059abed3801aafd6dbc1ed07a)
Revert "Have backendhousekeeper check for artwork update boolean."

This reverts commit 3798a07098272be9f04902ec71874b0d2fb1308d.
Add secondary check to prevent housekeeper task from running twice.

This adds an extra check to prevent a HouseKeeperTask from running
more than once simultaneously. This prevents an issue seen in a
misconfigured child task that was queued in concurrent passes. One
instance had not yet finished when the second one started a minute
later, and overwrote a shared pointer, eventually resulting in a
segmentation fault.

Cause spotted by Jonatan Lindblad.

Refs #11902
(cherry picked from commit c712ed04255fe416d95a674ed50e045d864759e8)
Add back ArtworkTask enable check... properly.

This adds the check for DailyArtworkUpdates back to ArtworkTask,
following its reversion in ca3a79bf407, but properly runs the
PeriodicHouseKeeperTask check so it does not requeue once per minute.

Refs #11902
(cherry picked from commit 7905afdd4fc7d9ee2eb1bf97bffe0f6e003cc1e9)
Bump binary version.
Add missing toUTC() conversions in the preview generator.

Without these conversions, modification timestamps on
backend-generated preview files are reported in local time, but
interpreted by the frontend as UTC.  The frontend then converts this
to local time and uses that to set the modification timestamp of the
locally cached preview, effectively back-dating the cached file in
most time zones.  This messes up date comparison logic for determining
whether to regenerate or reload the preview image.
(cherry picked from commit ad18e3d69c19ab6e197e15d285844ccb49e16795)
Mythutil: Allow --video instead of --chanid/--starttime.

This applies to the markup utils.  Refs #10804
(cherry picked from commit 97a309a04f017fcfbdb2004a12008e1f563b141c)
Add mythutil --getmarkup and mythutil --setmarkup commands.

This extracts the contents of the recordedmarkup, recordedseek, and
filemarkup tables to or from a local xml file.  The primary reason is
to allow users to extract recorder seektable information as needed and
attach it to a ticket, for a developer to use for debugging.  Example:

  mythutil --chanid xxx --starttime yyy --getmarkup /tmp/markup.xml
  mythutil --video zzz.mpg --setmarkup /tmp/markup.xml

An added benefit is to be able to copy metadata (e.g. seektable,
commskiplist, cutlist) between isolated MythTV instances.
(cherry picked from commit dafb81abcf8955112037d2e7e230ebb8eb068886)
Update binary version after [aaa418e].
Prevent the use of SendReceiveStringList() on a socket with callbacks. Fixes #11777
(cherry picked from commit 836eb11d96abfaa5986e7382103db69769b0ae47)
Make sure callbacks are disabled when the slave backend ANNounces.

Refs #11867
(cherry picked from commit 84fa3fe02d6731d06b4d64573253710405767923)
Disable MHEG/ITV when generating previews or flagging commercials
(cherry picked from commit bc62d105d6cd594e18c8d0674902916d3b00d37b)
Merge branch 'fixes/0.27' into stable/0.27