Added script aliases for test.js and benchmark.js

With the script alias...

The test runner can be run by simply calling

    npm test

and the benchmark script can be called with

    npm run-script benchmark

In the future, the tests can be broken into multiple files and run with 'npm run-script [test_name]' and the 'npm test' alias can be modified to run a full suite of tests at once as [demonstrated here](http://stackoverflow.com/a/20384739/290340).