add ipod-library support

Couldn't figure out how this was happening, so I don't want to hide it with try/catch. Let's get it fixed instead.

Merge caching changes into master

[WIP] Prevent errors on iOS when using text tracks with caching

Fixes a crash when using the cache & sideloaded text tracks together due to the tracks on the asset not being available. Re-visit when someone with more expertise on the cache can look at it.

Reorganize README

[WIP] Update ExoPlayer to version 2.8.2

Feat/ontimedmetadata android

ios Caching Support

Update NewtonSoft JSON to match react-native-windows version

Android - Keep screen on

Fix HLS Playlists (only support mp4, m4v and mov file extension)

Add debug logging for guiding library consumers about why their video is not cached