FIX view movies for guests and add feature test

Squashed commit of the following:

commit b5433d07c5715ac3a263ad04e4bb38e77f8c2129
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue May 21 10:09:43 2013 +0200

    Added feature test for watching a movie as a guest

commit e19a171d97b078cac9fcf90c3448d83586390484
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue May 21 09:53:51 2013 +0200

    Enabled Guest to view previews

commit 018eeafa36eb2d2f5691563a9968a3a21a7b41aa
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue May 21 09:11:49 2013 +0200

    Added tar of media_files_with_movie for feature test

commit 9037a54c2524ac9d3d0580450ddde964eb2cdca1
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue May 21 09:05:47 2013 +0200

    Personas db with movie to test public viewing