Add preferences action
Add icons resource
New layout: application actions sticking to the right edge
Adding drawer prototype
Fix preview frames scrollers

They were not properly updated when content was re-becoming smaller
than the scroller.
Moving settings markup to drawer
Adding SettingsController
Remove bad/deprecated TODOs
Initial quick design for right settings drawer
Move toggling code to settingscontroller
Nit: fix indentation
Small settings panel styles update
Adding simple backgorund picker (without persistence)
Adding TODOs related to namespace cleaning
Add basic UserSettings persistence static utility.

Based on localStorage for now.
Create an event based UserSettings and use it for the grid diplay state.
Fix travis
Fix cache typo in UserSettings
Clean grid code: semantic names and tiny refactor using UserSettings
Plug canvas background settings on UserSettings storage

Canvas background class are now manager at the FrameRenderer level
instead of CSS classes at the top of the DOM.