Minor refactoring
Refactored content script execution
Adding controller (in progress)
Fixed js loading
Migrating to backbone.js
Restoring features
Enable/disable buttons
Restored UI events (mostly)
Restored panel double-click functionality
Restored Drag'n'Drop
Refactored panel rendering
Minor fixes
Restored keydown, minor fixes
Restored overlay selection
Restored localStorage support
Cleanup
Fixed jquery ui image urls
Restored tracking, fixed arrows keydown
Fixed state saving
Merge remote-tracking branch 'origin/develop' into feature/refactoring

Conflicts:
	Extension/background.js
	Extension/manifest.json
	Extension/pp-content.js
	Extension/shared.js
	Extension/storage/pp-storage-filesystem.js
	Extension/storage/pp-storage-localStorage.js