[ruleset/{code-based, temporary}] Closure-rules for temporary ruleset
[blocked-image, ui/content-context-menu] Display placeholder on blocked images and add context menu for unblocking them
[popup] Hide rules containers if rulesets disabled
[popup] Rotation button rotate backwards on right click
[ui/popup, preferences-user-rulesets] Object and subdocument types support
[utils] createElement events support
[blocked-elements, content-context-menu] Placeholders for other kinds of
elements (onbjects and subdocuments)