Use common file to list qunit tests to run

Currently there are 3 ways to run the unit tests:

* qunit_test_runner.html
* karma.conf.js
* karma.conf-sauce.js

When adding more tests, you need to list the new test in each of those files. There should instead be a single file that all 3 of the above will import.

In addition, karma.conf.js and karma.conf-sauce.js should import the `proxies:` section from a common file - probably the same file as above.

Read qunit_test_runner.html, karma.conf.js, and karma.conf-sauce.js to compare their test lists and proxy settings. Define a shared file for the test list and have all three files import it; share the proxies section between the two Karma configurations as well.

Written by the indexing model from the issue text.