restores the enableWebfonts preference that displays a checkbox in the ULS Language Panel to toggle availability of webfonts
new global variable $wgULSWebfontsEnabled can be used to configure if fonts will be loaded by default in the wiki. Default value is true, to load fonts. (set to false for Wikimedia wikis)
removed the uls-enable preference that was introduced recently to disable ULS across Wikimedia wikis (on 2014-01-21)
ext.uls.webfonts.js initialization was changed to load a minimal possible JS Library code for webfonts; remaining code is loaded when user makes additional requests