When group submissions and blind marking are enabled, an error is thrown
when a teacher trys to download all submissions in a zip. The fix is to
move the url rewriting from the plugin to the assign class so it is
done in a standard way by all modules. The rewriting is done to make images
in a text editor field resolve correctly.
This was preventing the view full submission/feedback link from appearing
everywhere in the assignment when the submission/feedback content had been
truncated in the summary because it was too long (or too many files)
Damyon Wiese