fix timestamp and set content before getting btns

- file was not formatted corrected because the date formatter expects a
Date passed to the format method
- null pointer exception on activity launch because the activity was
  trying to find buttons that did not exist yet since the layout was not
  yet set to activty_audio_recorder

FIXME:
 - can't record more than once on the same activity
 - change 'pause' to 'play' after audio recording completes