compilation errors with latest development version of OCCT

[jffmichi]

Some recent commits to OCCT removed a lot of header files:

Open-Cascade-SAS/OCCT@14d4e9117

A lot of those headers are used throughout netgen which gives errors when trying to compile netgen using the latest development version of OCCT, e.g.:

[...]
libsrc/occ/Partition_Loop.cxx:47:10: fatal error: TopTools_ListIteratorOfListOfShape.hxx: No such file or directory
[...]
libsrc/occ/Partition_Inter3d.cxx:49:10: fatal error: TopTools_DataMapIteratorOfDataMapOfShapeListOfShape.hxx: No such file or directory
[...]

I fully understand if there's no desire to support some arbitrary development snapshot. However, at some point OCCT 8 should probably be supported and then those issues become more relevant.

Thank you all!