Added Firefox 27+ to the "notNeeded" browsers 

It does not have a tap delay when the content is not zoomable. More details in this bug - [https://bugzilla.mozilla.org/show_bug.cgi?id=922896](https://bugzilla.mozilla.org/show_bug.cgi?id=922896)

I have tested it with Geeksphone Keon running FirefoxOS 1.4 and Firefox version 30.