VE-169: Focus mode for VisualEditor
code review and jshint fixes
VE-169: z-index stacking order
showing and hiding focus mode on setup and teardown
VE-169 Fully remove focus widget when tearing down the surface
VE-169 Only add focus mode widget to the main surface - not surfaces in dialogs
VE-169 Fixing bugs from acceptance tests
VE-169 code review, performance
VE-169 using this.surface once defined
VE-169 semicolons
VE-856: Fix by adding !important to CSS that hides ads
Merge pull request #2778 from Wikia/VE-169

VE-169: Focus mode for VisualEditor