[ios] - remove the audiosession handling from the sink - its handled in the UIApplication already
[ios] - always send a speed change to ios when the player gets paused (to stop the playback progress bar in the ios control center)
[ios] - allow usage of IDispResource on the whole darwin platform (not only osx)
[ios] - allow to register IDispResource on iOS Windowing and call OnAppFocusChange when needed
[ios] - call OnAppFocusChange in windowing when app is backgrounded/foregrounded on ios
[guilib] - sanity check hw textures before deleting (on ios when backgrounded it seems that ios diddles with textures and might delete them away without xbmc knowing) - do the check only when ios windowing is backgrounded
Merge pull request #4350 from Memphiz/iosbgmusic

[ios] - restore the music background playback ability