Added grunt tasks to ease development

Grunt configuration has been added to run server startup, test and files watch tasks.

If you are not familiar with Grunt, all that you have to do is install it globally `npm install -g grunt-cli` and then you can run the tasks that are configured in the Gruntfile, for example `grunt server` will run the test suite, start the server and watch files for changes.

I included only bare bones Grunt configuration that you can expand on as needed.