Correctly take inline entity instances for select types into account in the Python wrapper
Use a char* instead of a std::string for the std::ofstream constructor
Return empty list when for ifc datatypes not encountered in file
Merge branch 'master' of https://github.com/aothms/IfcOpenShell
Fix for inline entity instance regression
Allow optional arguments to be set from Python with None, e.g:
    ifc_person.set_argument(0, None)
Merge branch 'master' of https://github.com/aothms/IfcOpenShell
Fixed string conversion error