Several improvements to capabilities and build.

- cmake fixed, no longer needs numpy headers.
- models can be loaded from an external interepreter.

src/PYTHON/python_impl.cpp

@@ -28,6 +28,9 @@
 
 #ifdef LMP_MLIAPPY
 #include "mliap_model_python.h"
+// The above should somehow really be included in the next file.
+// We could get around this with cython --capi-reexport-cincludes
+// However, that exposes -too many- headers.
 #include "mliap_model_python_couple.h"
 #endif
 
@@ -52,7 +55,6 @@ PythonImpl::PythonImpl(LAMMPS *lmp) : Pointers(lmp)
 
   nfunc = 0;
   pfuncs = nullptr;
-
   // one-time initialization of Python interpreter
   // pyMain stores pointer to main module
   external_interpreter = Py_IsInitialized();
@@ -61,7 +63,7 @@ PythonImpl::PythonImpl(LAMMPS *lmp) : Pointers(lmp)
   // Inform python intialization scheme of the mliappy module.
   // This -must- happen before python is initialized.
   int err = PyImport_AppendInittab("mliap_model_python_couple", PyInit_mliap_model_python_couple);
-  // todo: catch if error and report problem.
+  if (err) error->all(FLERR,"Could not register MLIAPPY embedded python module.");
   #endif
   
   Py_Initialize();