pybind11

With the current implementation, all python bindings are specified in header files located in pybind folders under each SMTK namespace, for example smtk/common/pybind/ and smtk/attribute/pybind/. In the current implementation, these files must be updated manually in conjunction with each API change in the corresponding C++ class. To support this, there is a script file at utilites/python/generate_pybind11_bindings.py that can auto-generate the bindings source files. This script imports the python pygccxml module, which in turn requires the CastXML library to be installed on your system.