Add infrastructure for server side jasmine tests

Using Grunt, add files necessary to run server side unit tests.  This
includes the default task, which will run jshint along with jasmine.
Include a .jshintrc file for the server side tests.
Add a letters-to-colors controller test

Add a simple test to help demonstrate the unit tests on the server side.
Add grunt watch

Add the grunt watch task to rerun the default task when a file changes.
 This helps when adding unit tests.
Add npm scripts for server side testing

Add a couple npm scripts to run unit tests for the server side.  Just
some flexibility, but in the end, grunt should be used to run both
server and client side tests.
Refactor letters-to-colors controller for testing

Pull out the functions and export them to allow testing of the logic
within the controller.