Design Changes and Security Fix

I made a few changes that I thought might be of some use:

* Refactored HTML and CSS to be more standards-compliant
* Redesigned search and config pages to be more consistent with the logo and each other
* Added support for message flashing
* Fixed #14 by salting and hashing HTTP auth passwords
  * This is backwards compatible so that users with plaintext passwords can still login, but the user will be warned that they should update their password for better security

Pictures of the new design:
![search-page](https://f.cloud.github.com/assets/1945829/1265932/63a08e42-2c79-11e3-9ff2-82eacd69e342.png)
![advanced-options](https://f.cloud.github.com/assets/1945829/1265935/79354d92-2c79-11e3-8a4d-4276f854e5b1.png)
![flash-message](https://f.cloud.github.com/assets/1945829/1265931/638e3b48-2c79-11e3-9a63-d1a0a2d0bcaa.png)
![slightly-nicer-config-page](https://f.cloud.github.com/assets/1945829/1265933/63a26fd2-2c79-11e3-89d5-86feaae21e9a.png)