GPII-183: Adding the buzz audio framework

Buzz is MIT licensed and will be used by the SelfVoicingEnactor for the audio playback.
GPII-183: Updated tts enactor to use buzz

Using the buzz html5 audio framework for the tts enactor. Also, removed the tts enactor from the iFrame as it should only be enabled in the main page.
GPII-183: Removes tts when not supported

Added in the progressive enhancement check to remove the TTS enactors and panels when it is not supported.
GPII-183: Fixed a type-o
Merge branch 'master' into GPII-183
GPII-183: Added a readme for buzz
Merge remote-tracking branch 'jobara/GPII-183'

* jobara/GPII-183:
  GPII-183: Added a readme for buzz
  GPII-183: Fixed a type-o
  GPII-183: Removes tts when not supported
  GPII-183: Updated tts enactor to use buzz
  GPII-183: Adding the buzz audio framework