Changed media to be a wrapper around HTML5 audio

http://github.rim.net/webworks/BB10-WebWorks-Cordova/issues/168

@bryanhiggins 
I found that there is a problem with the [mp3 used in the mobile spec] (https://github.com/blackberry/cordova-mobile-spec/blob/master/autotest/tests/media.tests.js#L138), the tests were stalling even with my change, I manually changed it to a [different one] (http://ev2013.fll.cc/FLL%20EV13%20Theme%20-%20I%20Dreamed%20of%20Love.mp3) then the tests no longer stall.

There are still 2 test failures which I don't understand.

Another difficulty that I ran into is I can't build the JS using `jake build`. In order to get around that for my testing, I had to run node manually and execute the packager myself. I wonder what is going on.