[Build] Remove fppversion.c during 'make clean'
[Networking] Enclose PSK in double quotes instead of single
[Sequences] Allow both PSEQ and FSEQ for our sequence header file.
[UI] Fix another issue with files getting linefeeds added on download.
[fppconvert] clone xLights from master.

dkulp notified me that the OpenGL branch has been merged in xLights and
further development is being done in the master branch now.
[Playlist] Bump max Playlist entries up to 128.
[UI] Fix helper function copy/paste error that gave unnecessary warnings
in our apache logs.
[plugins] Update big-red-button and vastfmt plugins to fix the bug in helper functions
[Help] Add a line break to GPIO help
[License] Add license file indicating fppconvert is GPL v3

The rest of FPP is GPL v2, but fppconvert uses xLights source code
so that makes fppconvert GPL v3.
[License] Add a license file for external components and their URLs
[Testing] Add a Channel and Sequence test screen to the UI.
[Debugging] Update debug log to show proper channel numbers
[Media] Add mediaOffset setting to allow adjusting sync offset
[Media] Add oggPlayer and mp3Player hidden settings

These allow overriding the use of /usr/bin/mpg123 and /usr/bin/ogg123
directly to allow testing outputs other than ALSA.
[Debugging] Remove sequence debugging from developer page

This is on the testing.php page now, so it doesn't need to be
duplicated on developer.php.
[MultiSync] Fix remote mp4 playback when master plays audio-only
Merge branch 'master' into networking