#326 — improvements for the Edit Blog screen in settings

I tried to be careful to use/improve existing WP style methods. I also noticed this controller is used for adding self-hosted blogs, so made sure that looks decent as well.

This is far from perfect. There are many other problems with the way these settings screens work. But I think it's an improvement.

Before:
![blogsettingsbefore](https://f.cloud.github.com/assets/515035/1489062/8c6c0036-4763-11e3-8b20-045478a45813.png)

After:
![blogsettingsafter](https://f.cloud.github.com/assets/515035/1489065/90f18a36-4763-11e3-9b8b-362381d740d2.png)