Various UI tweaks

- Use "fluid" layout that can expand to wide browser windows, instead of the old one's limit of 1200 px
- Remove unnecessary `<hr>` lines
- Switch back to Bootstrap's default theme
- Use Bootstrap's standard nav style
- Make headers more consistent between deploy and app UIs
- Replace some inline CSS with stylesheets

Here's a picture of what it looks like:
![screen shot 2013-08-31 at 4 08 05 pm](https://f.cloud.github.com/assets/228859/1063210/15a5e52e-1299-11e3-8849-c4218428cdf6.png)