Fixes bug making it impossible to pause video from controls

Examples working on android/ios again

Added isAsset same as iOS implementation

Fix the android version, and upgrade to react native 0.19

Closes #129

Example fix, test script, and some refactoring

- The test script just does an eslint check. (Closes #121)
- Refactored JS code to pass the check.
- Fixed VideoPlayer example. (Closes #117)
  - Updated package.json to use local react-native-video in a simple manner.
  - Added shared scheme for target.
  - Updated poject settings.
  - Now using react-native 0.18.1.

Introducing custom/native/embed skins

Android support

rate won't be supported on Android for a while as the native
MediaPlayer class doesn't support it either.

Remove seek from state.