Added grunt task and source maps

- Original 'grunt' task now provides source mapping
- Uglify was removed from it's own task and put into r.js task as it
comes with it. package.json was updated to reflect this.
- Running 'grunt build' will create a minified version of mylib.js
using uglify2. This can be switched out easily to uglify by updating
the gruntfile as uglify also comes with r.js