[WIP] Auto save draft posts

Issue #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)"


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The title being written over like that feels a bit odd. What if the title was set to "Your Post Title", so that the user can see "ah, it just defaulted to what was in the placeholder there."

I also, personally, like having NProgress fire on a save, but it could be that no one else will realize what just happened, whereas here I am literally counting down the seconds to it :P 
Can this be swapped out for:

`Ember.run.debounce(component, 'sendAction', 'typingPause', 5000);`?