Android: release the Android media player before destroying it.

Change-Id: I18715efd7ff346a9f6f2214727ec66ee79ad0d33
Reviewed-by: Christian Stromme <christian.stromme@digia.com>
Android: wait to have a valid video surface before loading a media.

Setting the video surface on the Android media player after it has
loaded the media doesn't work on some hardware.

Change-Id: I5e621a34ace9de458bfc65bfac8fa50c29cee9a5
Reviewed-by: Christian Stromme <christian.stromme@digia.com>