[PixelOverlay] Thread part of FPP::MemoryMap::TextMessage()
[Events] Close control socket when running an event script

If the user runs omxplayer from an event script, this could spawn
off a dbus-daemon process which could hold the fppd control port open
preventing fppd from being restarted.  We close the socket whenever
we spawn omxplayer for video playback, so close it in the event code
as well just in case.
[Audio] Add UI for configuring the mediaOffset Advanced Setting
[Developer] Add easy buttons to clear restart/reboot flags
[Sequence] Bump max channels allowed in .fseq up to 128K
[E1.31] Bump up max sACN/E1.31 universes to 256

If users use small universe sizes, then 128 universes is not enough for
the previous 64K channels supported by FPP.  This commit bumps up the
max number of universes to allow more than 128.  With FPP now allowed
to read up to 128K channels from a .fseq file, this higher limit makes
even more sense.