Release notes 1.7.19

Better messages and handling of bad data when importing AVETMISS80/85 files into onCourse.
Fixed a problem with the debtors report where the total was not the correct value.
Fixed a problem with class duplication where it could freeze onCourse client. The class list does not display progress until the duplication process is complete but all other windows will now be usable.
Prevented custom fields from being saved without a name. When they were saved without a name, they would cause contact details to not appear correctly.
Fixed a number of problems with students not merging correctly.
Class list report enhanced
- increased width of class code
- enrollments now totalled
- Fee with tax displayed
Class code, date and time added back to Tutor Class List report
Addition of SA AVETMISS flavour to AVETMISS export to allow for SA specific requirements.