Add shippable build file

Install yo globally
Remove check for yo
Add npm link
Add npm badge to README.md
Add global preferred installation option in package.json
Add 'npm run coverage' command in package.json to run test coverage
Copy the resulting code coverage xml file to the expected shippable location
Run code coverage at the end of a successfull build
Add travis CI file

Add global installation of istanbul
Merge pull request #6 from thaiat/feature-deploy

Add continuous deployment and integration with shippable.com and travisCI