Add special handling for text fields with the CLEANHTML type. This should
be used when students and teachers can edit the same field (you can't trust those students).
Applies cleaning on submitted data, and on data stored in the DB before it is put back in an editing form.
While this is not related to this issue, when reviewing it was
detected that the size of those url fields was really small and
looking decided to add this bit of normalization over existing uses.
Damyon Wiese