GPII-183

Switched the SelfVoicingEnactor to use the buzz framework. (http://buzz.jaysalvat.com, MIT licensed). This simplifies the code, provides checks for HTML5 audio support, and fixes the issue with Firefox not working properly. 

Using the checks from Buzz, we were able to implement graceful degradation of the tts related enactors and panels so that they are not used in environments that do not support them. Currently the tts server only supports wav files, so the checks are based on this. 

Had to upgrade Infusion to pull in the progressive enhancements framework into the custom infusion package.

http://issues.gpii.net/browse/GPII-183