+ fix memory leak (localDictionary) by replacing C API with PyCXX
+ don't write the whole code as error message if an error occurs. Python raises an exception with all relevant information for debugging
Until C++11 bit fields with integral types should have explicit signedness only.
It is implementation specific whether an -typed bit field is signed, so there could be unexpected sign extension or overflow.
This means that if depending on the compiler int32_t is not explicitly defined as signed the UnitSignature structure may not work
as expected. Since C++14 this has changed and an int of a bit-field is always signed:
https://stackoverflow.com/questions/33723631/signed-bit-field-in-c14
Since Py3.3: 'Py_ssize_t PyUnicode_GetSize(PyObject*)' is deprecated [-Wdeprecated-declarations]
Since Py3.9: 'PyObject* PyEval_CallObjectWithKeywords(PyObject*, PyObject*, PyObject*)' is deprecated [-Wdeprecated-declarations]
Since Py3.9: 'void PyEval_InitThreads()' is deprecated [-Wdeprecated-declarations]
