Clean up new post interface

### What happened?
- Removed the hero when logged in
- Added the ability to toggle the mark down preview in edit.
- Added the ability to edit the post slug
- Made auto save faster (1min now)
- Show notification about auto save if you've navigated away from the tab.
- Styled the alert
- Style the title to reflect what you're editing
- Styled buttons around the `cancel`, `toggle preview`, and `delete` buttons in edit.
- Post edit route now uses the ID instead of the slug. (This is so you can edit the slug)
- JS alert when clicking `delete` btn.
- Cleaned up deprecation warnings

![screen shot 2014-11-01 at 8 12 36 pm](https://cloud.githubusercontent.com/assets/2072894/4873774/fdd0a330-6224-11e4-8a70-a57242114687.png)

### What's left?
- [x] TODO: Add edit btn to post overview
- [x] TODO: Only run autosave once if the tab doesn't have focus