Added support for Travis-CI and many ruby-version. Only 1.9.3 leads to f...

Hi

Thank you for your work on Jenkins.  I am a happy user of Jenkins, eg. http://ngiger.dyndns.org/jenkins

Here I have a small patch to use the Travis-CI to run rake build/spec on a variety of ruby versions. 

As you can see under https://travis-ci.org/ngiger/puppet-jenkins many are okay, but there are failures for Ruby 2.0.0.

Best regards

Niklaus Giger