Express server and Karma runner

Express server that listens on http://localhost:4567 so that any browser can be used.
Just have node installed and do `npm install` for dependencies and then `node server.js` to run the server.

Karma config
After installing dependencies with npm, startup the automatic test runner using `./node_modules/karma/bin/karma start`.
Any time a file is changed (test or app) the tests will automatically rerun and show the results on the command line.