Add optional, multilanguage versioning

Hello, I added optional, multilanguage versioning (read only for now) to the gem, the versioning was silently not working for 'master' so I moved back to a stable commit and started a new branch 'versions-stable' 'from there, I am planning to release the gem soon, but I would be glad if you could merge my 'versions' current branch with your 'master' if you can get it to work with the latest refinerycms and versioning, for now I will stick to older/stable 'versions-stable', so feel free to modify gem dependencies and fix 'versions' branch to get it working with your latest work.

![screen](https://f.cloud.github.com/assets/34706/938755/f2ef40f2-0104-11e3-81c4-dfa163b979eb.png)