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
[gui] scrolling text could be truncated because scrollInfo.pixelPos was treated as pre-scaled when it wasn't. fixes #14629
[WIN32] basic implementation of a IMMNotificationClient interface to notify XBMC in case of audio device changes.
[WIN32] hook up audio engine to device changes.
cosmetics
[gl] support YUV420P10->RGB in software renderer
Merge pull request #4264 from jmarshallnz/scrollfix

[gui] scrolling text could be truncated
Merge pull request #4257 from wsoltys/notify

[WIN32] hook up CAEFactory::DeviceChange() to audio device changes
[language] change "now playing.." in sidemenu to something more obvious as it also shows when not playling anything.
Merge pull request #4265 from MartijnKaijser/now_playing

[language] change "now playing.." in sidemenu
[WIN32] remove harfbuzz library as its already compiled within our "internal" libass (see https://github.com/xbmc/libass)
[language] split of "Add-on disabled" string after d6886825312ec575a3232e465a8837e600c2f11f