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