Autosave Draft posts

Ref #1413
- If the user stops typing for 5 seconds, a "typingPause" action is sent from the GhCodemirrorComponent
- Editor-base-controller ties the "typingPause" action to its "autosave"
- If a post is being autosaved and does not have a title, the title is set to "(Untitled)"
- Cleanup editor base controller property dependencies and code