Define if source or target is connected with visualReview on import

Current situation: When importing a task translate5 automatically decides, if the target language or the source language is linked to the content of the layout.

Future scenario:

• there is a new import option, that defines if the layout is linked to source or target language. This import option has three choices:
  • Define automatically (default, if nothing is selected)
  • Source
  • Target
• In the GUI this is implemented as a drop down below the field "PDF for VisualReview", that is only visible, if the visualReview plugin is active.