add translate link field

I recently needed to add a 'translate' link on a node data view, where the translate link points to 'node/xxx/translate'. I was able to do it with the global text, but then none of the permissions and other checks (e.g. are translations allowed for this content type) weren't done. This meant the link appeared regardless of the node type, the user, etc, and when clicked on often returned a 'access denied' error. Really this link needs to be provided by a views field handler.

Attached patch adds this functionality to views/modules/translation.views.inc

Cheers,
Stella