Remove redundant QObject:: prefix from some tr()

The class in which these tr() are called already inherit from QObject
so it can be called directly without using the QObject:: prefix.

This has the effect of changing the translation context to a more
meaningful one...
Add some new strings in the (Common) context.

At the same time, fix one of the strings in another class so that it's
written in the same way...
Miscellaneous translation fixes

Add some more strings in the (Common) context.

While there, make tr() usable directly in that class.
Change log type for RAOP
Add multiple UI display dependencies support.

Operators supported are & (AND) and | (OR); priority are strictly from left to right. If a dependee doesn't exist, it's considered as in unvisible state rather than just ignored
Make no-artwork condition themeable.
Update default notification theme to support no artwork condition
Add image from Artist: Vargas21 http://www.iconarchive.com/show/aquave-metal-icons-by-vargas21/Music-icon.html
MythGallery translation context changes
Merge branch 'master' of code.mythtv.org:mythtv
Mark two new strings for translation.

Those strings weren't marked for extraction but we were trying to retrieve
their translation later.

At the same time, change the strings lookup context...
We want the notification screen stack to be displayed from oldest to newest, we want all windows to be animated when deleted and pressing ESC should remove the oldest notification first

Lots of copy/paste; main MythScreenStack should handle this, but as to not break anything, limit the changes to the notification center.

Fixes bug #11683
Fixes bug #11685
Do not re-create a notification center if one has already been created.

Reloading the theme would cause a 2nd notification center to be created the previous one leaking
Fixes bug #11684
Do not reload the entire notification screen whenever we're about to display it.

This caused the images to be reloaded 70 times per second, preventing images to be loaded in the background
Add flag to mark if screen needs to be refreshed or not.
ResetMap should reset textarea widget using the same logic they were first set

Fixes #11687
Add missing header
Make consistent use of InfoMap datatype.

There was about 3 different "map" formats. All ultimately expected to convert into InfoMap has used by MythUI.
Make their use consistent, and if it's to be used as InfoMap, then make it an InfoMap.

The ultimate test being that you should easily be able to change InfoMap from being a QHash to a QMap and it would still compile.

Also, make InfoMap argument a const, if it's used as such.
Remove compilation warning

Expecting code error there too
Make consistent use of InfoMap datatype

follow up on b44a73ea42e7cc66a7766b7e8a2b8c55830233fc
MythNetVision got missed.

Also removed non-required headers
Fix display of current position in an audio-only recording.

Once the decoder drains, we fake-increment the frame count so the
current position looks reasonable in the OSD, rather than appearing to
stall.  Refs #11357.