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.

![screen shot 2014-11-01 at 8 12 36 pm](https://cloud.githubusercontent.com/assets/2072894/4873774/fdd0a330-6224-11e4-8a70-a57242114687.png)