Fix translation views so that the correct from and to languages are show...

Fix done at the Plone Arnhem Sprint for issue #80 where the translation view shows the wrong from an to languages when working with Archetypes content. 

@bloodbare. You asked to check if the changes still work with Dexterity as well. I checked the  by
* using the same patch on a clean site
* installing p.a.contenttypes 1.0, 
* convert the default site content to Dexterity,
* installing p.a.multilingual ,
* add an extra langageu, 
* do the p.a.m setup
* and translate some content.

However: when I did this the p.a.c DX Folder CT had the multilingual behaviour attached, the DX Page CT did not. So as soon as I navigated to a page I couldn't translate it or see the language switcher. Enabled the behaviour on the page CT manually and then translation pages also worked.