Fix/avplayer release

[CHaNGeTe]

Release AVPlayer instance. Fixes some errors about: Decoder busy, etc.

[CHaNGeTe]

Related issues:
#1785
#1774

[jenshandersson]

@CHaNGeTe are you still active here? :) I think this PR looks legit. At least it shouldn't hurt to set to nil in dealloc

[CHaNGeTe]

Being honest, I am bit disappeared haha.
Let's move forward with that one then.
@cobarx @benoitdion any input for this one?

[enigmablue]

Hi yes, i'm also waiting for this - am getting -11839 avfoundation errors, especially with multiple videos that seems to be playing at the same time

[kdzapp]

Tested this branch w/o success in terms of fixing original issue. Any suggestions?

{ localizedDescription: 'Cannot Decode',
     domain: 'AVFoundationErrorDomain',
     localizedFailureReason: 'The decoder required for this media is busy.',
     localizedRecoverySuggestion: 'Stop any other actions that decode media and try again.',
     code: -11839 },

[dancixx]

This can be useful: https://github.com/abuelwafa/react-native-modern-video-player

[stale]

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