Fix "Main Thread Checker: UI API called on a background thread:" warnings
there are multiple warnings that we need to fix
2017-07-29 23:16:11.209731+0200 VLC-iOS-no-watch[84200:12602857] [reports] Main Thread Checker: UI API called on a background thread: -
[UIView setNeedsLayout]
PID: 84200, TID: 12602857, Thread name: (none), Queue name: com.apple.root.default-qos.overcommit, QoS: 21
Backtrace:
4 VLC-iOS-no-watch 0x000000010a3cf078 -[VLCTimeNavigationTitleView setHideAspectRatio:] + 136
5 VLC-iOS-no-watch 0x000000010a3f398e -[VLCMovieViewController displayMetadataForPlaybackController:title:artwork:artist:album:audioOnly:] + 702
6 VLC-iOS-no-watch 0x000000010a3e2547 -[VLCPlaybackController _updateDisplayedMetadata] + 2407
7 VLC-iOS-no-watch 0x000000010a3e1b66 __47-[VLCPlaybackController setNeedsMetadataUpdate]_block_invoke + 38
8 libdispatch.dylib 0x00000001147cd354 _dispatch_client_callout + 8
9 libdispatch.dylib 0x00000001147d3718 _dispatch_continuation_pop + 967
10 libdispatch.dylib 0x00000001147de7a7 _dispatch_source_invoke + 681
11 libdispatch.dylib 0x00000001147d1ecd _dispatch_queue_override_invoke + 733
12 libdispatch.dylib 0x00000001147d8ff7 _dispatch_root_queue_drain + 772
13 libdispatch.dylib 0x00000001147d8caf _dispatch_worker_thread4 + 44
14 libsystem_pthread.dylib 0x0000000114c405a2 _pthread_wqthread + 1299
15 libsystem_pthread.dylib 0x0000000114c4007d start_wqthread + 13
2017-07-29 23:18:35.609533+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:35.609772+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:35.610330+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:35.610577+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:35.610821+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:35.610996+0200 VLC-iOS-no-watch[84200:12602857] [Assert] Cannot be called with asCopy = NO on non-main thread.
2017-07-29 23:18:36.173044+0200 VLC-iOS-no-watch[84200:12689907]