test-framework: New Config UI / Settings Page

Here is the new test-framework Config UI that I designed. A few days ago, I sent an email to markus-dev asking for feedback, and the feedback was positive. 

Changes to the UI design:

 * Each test script and test support file is inside a box, and you can sort the boxes (for test scripts only -- test support files do not have an ordering to them)
 * The boxes can be collapsed and expanded.
 * If you check the "Remove" checkbox, the input fields for that test script will be disabled.
 * If you upload a test script, the file name in the legend should update immediately.

Some information about the code:

 * I added a "download" action to automated_tests_controller.rb so that admins can download test scripts and test support files that they've previously uploaded.
 * I used a lot of jQuery. As @darynl and I discussed on IRC, I have kept some existing Prototype code around and used  the `jQuery.noConflict()` function. In any jQuery code that I wrote, I used `jQuery` instead of `$`, the latter of which is used by Prototype.
 * I have placed my Javascript and CSS code in new files (`public/javascripts/testframework_config.js` and `public/stylesheets/TestFrameworkSettings.css`)
 * To use jQuery, I used a CDN link. I did not include the CDN link in my commits.
 * I do not speak French, so the text in `config/locales/fr.yml` are all just "UPDATE ME"
 * In the March 6 commit, I merged in @umsmit32's fix for the functional tests. The tests all pass still (except for two which fail in the master branch too).