configure.in: enable FFMPEG static build for ARM, some cleanups. Tested on i686, x86_64, arm (RPi & Cubox-i).
[epg] don't use epg tag that was active as a currently active one if epg contains gaps
[id3v2] some apps write TXXX tags using UPPERCASE and some with lowercase. Support both.
AESinkPULSE: Let Engine handle our volume
[addons] don't group add-ons into categories in disabled and available update sections of the add-on maanger
[addons] allow GetAllOutdatedAddons to return the local addon versions - useful for scheduling updates
[busydialog] factor out the dvdplayer busy dialog waiting so as to use it for other things
[addons] add 'Update all' item to the available updates menu
[addons] notifying the user once during repo updates is enough
[WIN32] remove harfbuzz library as its already compiled within our "internal" libass (see https://github.com/xbmc/libass)
depends: fix already installed check on osx

Avoid depending on .so files which could be .dylib on osx
Fix some invalid dependencies
Merge pull request #4269 from wsoltys/cleanup

[WIN32] remove harfbuzz library
Merge pull request #4260 from jmarshallnz/addon_improvements

Addon improvements
Merge pull request #4154 from sraue/ffmpeg-static-fixes

configure.in: enable FFMPEG static build for ARM, some cleanups. Tested ...
dvdplayer: [fix] subtitle priority for multiple...

external subtitles
omxplayer: [fix] subtitle priority for multiple external subtitles
Merge pull request #4251 from ThiasDE/extsub_priority

dvdplayer: [fix] subtitle priority for multiple external subtitles
[subsCore] close search window if playback is stopped
Merge pull request #4267 from amet/close_subs_window_on_stop

[subsCore] close search window if playback is stopped
Merge pull request #4258 from fritsch/aefixes

AESinkPULSE: Let Engine handle our volume