Add .ruby-version, .ruby-gemset
Add Jasmine gem

Generate installation files with `jasmine init`
Add Travis-ci, update README

The Headless Jasmine Boilerplate is a great source of inspiration
to integrate the JAsmine gem with Travis-ci,
see https://github.com/briangershon/headless-jasmine-boilerplate
Merge branch 'chore-add-jasmine-gem'