refactored research_assistant_controller a little + some tests
added two users_controller tests
adjusted some tests
removed unused student factory
made user factory a little more robust regarding status objects
made helper spec a little more flexible. Translation behaviour seems indeed a bit off between programming_language and language
more tests + refactorings, including #165 and #166
implemented application cancelation for #156
Merge pull request #172 from tkowark/develop

Merge the upload fix into develop-ak
lets make travis green again
merged develop-ak into develop