Make it easier to authenticate in dev environment
Refactor button styles and make them apply everywhere

This extracts styles for buttons into a separate stylesheet, and makes 
them apply to Formtastic buttons as well as links. This also adds 
Firefox support for button gradients.
Tweak Formtastic error styles
Refine a few more styles

- Remove the list bullets from the history table
- Adjust the margin on the 'on loan since' text
- Keep consistent font sizes on buttons
Make the book and copy pages share the copy view
Redesign the 'add a new copy' form

This was probably the worst bit of UI in the app. I've rebuilt it to 
be a lot easier to use.
Tell Travis to use Ruby 2.0.0