new spin box that enables subsdelay filter and disables it when the value is set to 0
the spin box tooltip and suffix are updated according to the subsdelay mode
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

The thread are already created with the right priority. If not, then
vlc_clone() should be fixed instead.
Also, the vlc_thread_set_priority() calls on the main interface thread
seem bogus, as the target thread is dedicated to monitor the libvlc
death and is not the main running thread.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Close #4776

Useful for people with accessibility difficulties. No icon yet.
Close #2253

They are not used by modules anymore.

Close #4092

refs #4734

One is the actual URL, the other is a metadata
Close #4157

Close #4341

Close #4818

This would close #4321 , if cli.lua vout function were working

It now uses vlc_clone()
It is started only when needed.
It does not uselessly poll every 100 or 10 milliseconds anymore...

Regression introduced by commit 4a590357.

Identity is not a method but a property
"" is not a valid object path