remove Artist from Controller list in TestApp.pm because it does not need to be injected
improved test comment
add check if controller has 'move_to' action if Sortable trait is loaded
added missing test names
add move_to buttons to test TT template. Improves usability for manual testing/debugging
bugfix in tests. added missing error_path attr to Artist Controller
show albums and concerts in test template. (preparation for prefetch test)
add prefetch functionality
use new prefetch feature, no proper test yet