updating translations from launchpad
Merge pull request #425 from jdragojevic/update-translations

updating translations from launchpad
bz19958: fixed conversion menu.

Made a new way of handling the conversion items.  Now the backend
sends a list of (identifier, title) tuples to the frontend.  I think
this is cleaner than the frontend accessing conversion_manager.
Made the item context menu use the same system as the conversion menu