Pauses or resumes the video and/or audio stream.

def pause(self):
		""" Pauses or resumes the video and/or audio stream. """

		# Change playback status only if current status is PLAYING or PAUSED 
		# (and not READY).
		logger.debug("Pausing playback")
		if self.status == PAUSED:
			# Recalculate audio stream position to make sure it is not out of
			# sync with the video
			self.__calculate_audio_frames()
			self.status = PLAYING
			self.clock.pause()
		elif self.status == PLAYING:
			self.status = PAUSED
			self.clock.pause()