Added some tests

see issue #7

Test creation of following expected files (`dest` is the destination folder):

    dest/long/path/index.html
    dest/index.html
    dest/sitemap.xml
    dest/robots.txt

Test the content of:

    dest/long/path/index.html
    dest/index.html

To run the test run `npm test`
Yo may need to run `npm install` as I gitignore node_modules to keep the repos clean after adding 2 more dependencies: grunt-contrib-clean and grunt-mocha-test

We may need to add more tests.