Bug 1036848 - Fix location of shared modules (/firefox/lib vs. /lib)/ r=aeftimie, r=amatei, r=hskupin

--HG--
rename : firefox/lib/addons.js => lib/addons.js
rename : firefox/lib/endurance.js => lib/endurance.js
rename : firefox/lib/localization.js => lib/localization.js
rename : firefox/lib/modal-dialog.js => lib/modal-dialog.js
rename : firefox/lib/performance.js => lib/performance.js
rename : firefox/lib/screenshot.js => lib/screenshot.js
rename : firefox/lib/tests/testPerformance.js => lib/tests/testPerformance.js
rename : firefox/lib/widgets.js => lib/ui/widgets.js
rename : firefox/lib/utils.js => lib/utils.js