1 - Reports the error to the user in a popup.
2 - Names of the backups include the timstamp instead of a number. Names have more sense and the files can be sorted by names what is also the age order.
3 - Behaviors when changing configuration improved, the number of files present on the system was not reduced when reducing the number of backups or backups deactivated.
- we must read out the unit system description UTF8 to get the characters ² and ³
- update unit system description according to today's unit "cft" addition
- don't hardcode the unit system descriptions in the .ui file
- add acceleration to imperial schema
add convenience method getAllDerived()
support TypePy asrgument in getAllDerivedFrom() and isDerivedFrom()
return TypePy instead of str in getAllDerivedFrom()