spark 8.x-1.0-alpha7

- Now uses CKEditor, rather than Aloha Editor, per http://buytaert.net/from-aloha-to-ckeditor
- Incorporates "Unified In-Place Edit" concept from #1882482: [meta] Unify editing approaches in Drupal and http://buytaert.net/spark-update-unified-in-place-editing. (in progress)
- Various fixes to block, menu, etc. forms as a result, including long-time UX headache "List links" and "Edit menu" are now one page! #663946: Merge "List links" page into "Edit menu" page
- Layout preview bar: #1880606: Introduce a configuration UI for theme-based breakpoints (in progress)
- Redesigned content creation page #1510532: [META] Implement the new create content page design (in progress)
- Removing a bunch of core patches, since Edit and
Editor module made it into D8 core. Yay! :D
- Also removed all the Layout stuff, since this got blocked on upstream D8 architecture progress. :( Will have to be contrib at this point. :(
- Removes unused contrib modules.
- Fixed #1810258: PHP notices thrown in interactive installer.
- Contextual links now accessible. #849926: links wrapped in .contextual-links-wrapper divs are not accessible at all via keyboard alone also problems with screen readers