Dear developers.

I have made a substantial change to the survey translation screen:
  1. Grouped related topics on the same page.  For example, Survey title and description are on the same page.  Likewise, question group and group help, etc.  This partially implements a suggestion by Menno.  In my view this is a big improvement, since it reduces the number of tabs and keeps the translation context.
  2. Started to add support for translation of email templates.  At the moment, I have only coded the invitation email and the reminder email.  
Other changes:
Questions and issues:
As always, feedback is welcome.