Add test script to package.json

There doesn't appear to be a makefile associated with the project, so
I've assumed the 'make test' command previously listed in scripts was
boilerplate and just blown it away.

Using ./node_modules/.bin so that a developer doesn't (necessarily)
need mocha installed globally on their machine before getting started.

This commit makes 'npm test' run in the project root work as expected.
Use spec reporter for Mocha tests.

This is a matter of personal preference, but hot damn do I love seeing
unicode ticks.

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Merge pull request #316 from davidbanham/test_script

Make 'npm test' work