Add Gruntfile to test and lint the code from the command line
Add Grunt tasks to run tests against the minified code

This follows the general model used by WordPress Core to test minified code:

1. Copy the existing QUnit file, modifying it to point to the minified scripts instead of the regular ones
2. Run the same QUnit suite against both versions of the test HTML file
Enqueue minified version of the script file unless SCRIPT_DEBUG is “true”
Merge pull request #6 from kadamwhite/add-gruntfile

Add Gruntfile to automate testing & building from the command line