MOTM-504: Subscribing to topic newsletters not working correctly
added custom code in ListApi because I had trouble with zend form validator.  the better fix would be to add
a hidden form field for the Themen array with a value of "" that gets posted to the form and forces the Themen groups
list to be overwritten
Merge branch 'zplus' of https://github.com/thnkloud9/Newscoop into zplus