add create alert util function, bug fixes
add alert container
return error responses
use alert util function
use alert util function
use alert util function
bug fix: json description in variable selection
bug fix: ShoppingCart should be serializable
Merge pull request #878 from dennishendriksen/master

Various catalog bug fixes and small improvements
use single instead of double quotes
remove unused code, small fixes
fix test
Merge pull request #879 from dennishendriksen/master

Catalog: Small fixes and improvements
remove unused test
use StudyDataRequest.MOLGENISUSER instead of hardcoded string, update docs
remove unused mocking
remove unused method, move update to UserAccountServiceImpl
remove unused method, move update to UserAccountServiceImpl
remove unused method, move update to UserAccountServiceImpl
add tests