Update getting-started.md

Corrected twitter bootstrap repo link to:
https://github.com/twbs/bootstrap

The older url https://api.github.com/repos/twitter/bootstrap returned a 404 error and is not what getbootstrap.com is pointing to.
Update getting-started.md

Corrected the url in the example so it demonstrates invoking the api.
Merge pull request #341 from devdiva/master

Fixed link in getting-started.md example