added user import
importer refactoring
moved error handling in front of actual processing
Add dataTables to semester results overview tables with sorting and filtering
Put arrows to the left of the header texts
Sort responsible contributors by last name
Prevent text wrapping in table head, decrease size of type column
Add extra class to the tables in order to only select these for conversion
Update German translation of 'Search:' string
Merge pull request #362 from PFischbeck/course-result-sorting

Table sorting and filtering for semester result overview
Merge pull request #356 from janno42/user_creation

added user import
group results by contributors
refactoring and indentation fixing
changed related names
make "no answer" initial choice in questionnaires
added collapsibles for all contributors in a course's questionnaire
fixed test
refactoring
added buttons to skip contributors during feedback, removed the initial answer
language updates