Before, when you resumed the app the player would **always** start playing again.
After this changed the `paused` prop of the `Video` component (which is the `isPaused` variable internally)
is consulted on resume for whether or not the playback should resume as well.
* added listener for timedMetadata event.
* added callback in RCTVideo for the timed metadata
* exposing onTimedMetadata to JS
* added forgotten method declaration
* returning array of string values
* added metadata type to the array
* added onMetadata method
* overridden onMetadata method on exoplayer2
* added format of return value from onMetadata
* added function reference in README file
