Added protections to avoid exceptions for null objects.
For reading entity StepShape_ToleranceValue was added reading lower and upper bounds represented by entities "StepRepr_ReprItemAndMeasureWithUnit" or "StepRepr_MeasureRepresentationItem"
Automatic upgrade of OCCT code by command "occt_upgrade . -nocdl":
- WOK-generated header files from inc and sources from drv are moved to src
- CDL files removed
- All packages are converted to nocdlpack