Add Nodeunit for testing.

 On branch master

	modified:   README.md
	new file:   bin/run_tests.js
	new file:   manage.sh
	modified:   package.json
Full switch to Nodeunit testing.

 On branch master

	modified:   package.json
	deleted:    test.js
	new file:   test/test.js
promise.then() accepts a failure handler.

 On branch master

	modified:   index.js
	modified:   test/test.js