2.5: RNA, defining enums, pointers and collections properties is now

possible from python, but it's still work in progress.

Pointers and collections are restricted to types derived from
IDPropertyGroup (same as for operators), because RNA knows how to
allocate/deallocate those.

Collections have .add() and .remove(number) functions that can be
used. The remove function should be fixed to take an other argument
than a number.

With the IDPropertyGroup restriction, pointers are more like nested
structs. They don't have add(), remove() yet, not sure where to put
them. Currently the pointer / nested struct is automatically allocated
in the get() function, this needs to be fixed, rule is that RNA get()
will not change any data for thread safety.

Also, it is only possible to add properties to structs after they have
been registered, which needs to be improved as well.

Example code:
http://www.pasteall.org/7201/python

source/blender/python/intern/bpy_rna.h

@@ -75,10 +75,13 @@ int pyrna_pydict_to_props(PointerRNA *ptr, PyObject *kw, int all_args, const cha
 PyObject * pyrna_prop_to_py(PointerRNA *ptr, PropertyRNA *prop);
 
 /* functions for setting up new props - experemental */
-PyObject *BPy_FloatProperty(PyObject *self, PyObject *args, PyObject *kw);
-PyObject *BPy_IntProperty(PyObject *self, PyObject *args, PyObject *kw);
 PyObject *BPy_BoolProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_IntProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_FloatProperty(PyObject *self, PyObject *args, PyObject *kw);
 PyObject *BPy_StringProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_EnumProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject *kw);
 
 /* function for registering types */
 PyObject *pyrna_basetype_register(PyObject *self, PyObject *args);