Setting things up to enable testing with headless browser

* Load mocha & chai directly via script tags in test/test.html
* Remove instructions for async load of mocha & chai --- DRY
* Update call to mocha.run to accomodate PhantomJS
Add grunt test task

* Add grunt-contrib-connect to devDependencies
* Add grunt-mocha-phantomjs to devDependencies

NB: the more popular grunt-mocha fails due to some
conflict with requirejs loader … or whatever.