New test for linking of non-existing and existing properties via a form. The idea of the test is to track all create and set operations and afterwards compare that they occurred as expected. Sorry for the peculiar syntax for the expected updates to the database -- this should be one line for each update... An a bug-fix: I've reverted a change from April in roundup/cgi/actions.py that broke linking of messages to issues. The tests above now catch that. I couldn't figure out what the change was meant for, sorry if I broke something here.