Fix "Current fanart" not being shown in DialogVideoInfo.

I'm not sure why and I didn't investigate further, but a combination of early
unpacking the fanart and accessing the CFileItemPtr in place of the CFileItem
fixes the issue.

(cherry picked from commit 7f1a748935cbd95f638ba03e4d819d3567d71068)
dvdplayer: update dropping stats after every call to decode
[Keyboard Layouts] Add Polish QWERTY
musicdb: fix conflicting "singles" filter option introduced by 9fbf13eded5d682d4ae210043e536895c9356c18 (fixes #15539)
changed: Rename confusing CSimpleDoubleCache class to CDoubleCache
Merge pull request #5785 from Montellese/fix_no_songs_in_years_15539

musicdb: fix no songs being shown in years node
Merge pull request #5771 from hudokkow/pl_keyboard

[Keyboard Layouts] Add Polish QWERTY
fixed: FileCache-full logic was wrong + implement GetMaxWriteSize() function
fixed: Don't keep reading source when cache is full (fixes #15500)
changed: Use m_StateInput else dvdplayer osd info is 8 seconds delayed
fixed: Calling WaitForData with a large minimum could cause it to block the max. timeout
fixed: Typo in variable name
[repo] change repo URLs to use mirrors.kodi.tv
Merge pull request #5787 from MartijnKaijser/repo

[repo] change repo URLs to use mirrors.kodi.tv
[release] bump to 14.0 beta4
Merge pull request #5713 from anaconda/fix-curfanart

Fix "Current fanart" not being shown in DialogVideoInfo.
Merge pull request #5708 from arnova/double_cache_inthread_fix

Double file cache fix. Fixes ticket #15500
re enable manually add to library
[rebrand][win] new app icon
[rebrand][linux|upnp] new icons