Fix for FirefoxOS, which doesn't support :active:hover CSS selectors
Fixed slider knob press-highlight on FirefoxOS
Updated FirefoxOS button state workaround to use enyo.platform.firefoxOS
Merge pull request #134 from JayCanuck/master

Workaround for FirefoxOS, which doesn't support :active:hover CSS selectors.

Reviewed-By: Ben Combee (ben.combee@palm.com)