Issue #160 Add ruby 2.0.0 and 2.1.0 to travis
json gem is only needed in ruby 1.8

And causes an issue with bundler 1.5
https://github.com/bundler/bundler/issues/2780
Allow failures in travis for ruby 2.1.0

Puppet is broken in ruby 2.1.0
https://tickets.puppetlabs.com/browse/PUP-1243
Merge pull request #163 from rodjek/ruby-2.1

Add ruby 2.0.0 and 2.1.0 to travis