Contextual save/commit buttons
Warning messages when a page has unpublished commits

'Unpublished' being not-yet-live commits, for whatever reason.
Added copy to Unpublish page
Added tests for WidgyPage admin page buttons.
Removed unused clean_status.
Added commit_is_ready method to VersionTracker.
widgypage_change_form.html belongs in widgy_mezzanine, not page_builder
Test WidgyPage save actions
Remove django.fusionbox.scss

It had more than one purpose. Moved the history page styles into their
own file, and moved widgy-tools into widgy_theme_default.
Rearranged WidgyPage buttons
history.html belongs in widgy, not widgy_mezzanine