Fix issue causing PFMs to crash in PotS

Recall that PFMs are added as modules to the global modules dict.
Therefore, module names must be valid Python 2.x identifiers. This is
handled well for age names, but we've been neglecting to handle it for
PFM names. So, when Blender adds ".001" as a suffix to a duplicated
object, any attached PFMs will go down in a firey dust explosion.
Generally, with the unhelpful error message: "NULL result without
error in PyObject_Call".

korman/nodes/node_python.py

@@ -19,6 +19,7 @@ from contextlib import contextmanager
 from pathlib import Path
 from PyHSPlasma import *
 
+from ..korlib import replace_python2_identifier
 from .node_core import *
 from .node_deprecated import PlasmaVersionedNode
 from .. import idprops
@@ -305,6 +306,12 @@ class PlasmaPythonFileNode(PlasmaVersionedNode, bpy.types.Node):
             if i.attribute_id == idx:
                 yield i
 
+    @property
+    def key_name(self):
+        # PFM names ***must*** be valid Python identifiers, but Blender likes inserting
+        # periods into the object names "Foo.001" -- this causes bad internal chaos in PotS
+        return replace_python2_identifier("{}_{}".format(self.id_data.name, self.name))
+
     def _make_attrib_socket(self, attrib, is_init=False):
         new_pos = len(self.inputs)
         if not is_init: