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 saved and does not have a title, the title is set to "(Untitled)"
- Cleanup editor base controller property dependencies and code
Merge pull request #4259 from novaugust/auto-save

Auto save draft posts