WIP on js-testing: Karma conf that works

Run "karma start" in the test/ directory, then run "karma run" from
another terminal window, and the test will run. Or you can also do
"karma start --auto-watch" in the test/ directory, and it will rerun
the tests when any of the watched files change. ("The watched files"
means whatever is listed in karma.conf.js under "files").

Note that no runner.html file is needed for this; karma supplies its
own HTML to the browser. All you need is to supply the Javascript
files that define the tests, and the code under test, and Karma does
the rest.