Implement playback rate for Android 6.0+

Clear the progress timer on iOS when onEnd is reached

Document fullscreen callbacks fix #861

Add missing prop for enabling fullscreen

Forgot to include comment about disabling ExoPlayer fullscreen

Enable fullscreen UI mode for ExoPlayer

Fix playableDuration in onProgress & return seekableDuration

add seekableDuration to Android

Add requiresMainQueueSetup method

fxied an issue that does not use passed argument

Add link to propTypes

Document poster prop

Since RN 0.49, `requiresMainQueueSetup` needs to be defined if the module overrides `constantsToExport`.

- Version locked to 6.0+ because that is the version that introduced setPlaybackParams
- Ignores rate prop as before on android versions lower than 6.0

* Remove depreciated createJSModules @ovveride marker

* Remove depreciated createJSModules @ovveride marker

* Added comment in exoplayer

* Added comment

* Remove trailing spaces

* Fix typo in comment

* Fix typo in comment

* Fix typo in comment

* Fix typo in comment

* [tvOS] Update podspec

* [tvOS] Add tvOS target

* Update README.md

* [docs] Folder that contains pictures and content for documentation

* tvOS Readme

* [JPEG] Update image to JPEG