Reset window size when starting playback, otherwise Samsung Maple 5 (2010) device plays the video at its native resolution
Don't set display size for audio
Handle Samsung 2010 device returning -1 on failure

The Samsung 2010 device returns -1 to indicate a failed API call, rather than 0 (other devices) or false (as documented). Update checks against JumpForward(), JumpBackward() and Pause() calls to take this into account. Refactored and added to the tests to cover the case where devices return false for failure, even though none of the ones we've tested do.