Changed the script UI registration to import rather then run each python script,

this means it caches the compiled pyc files after importing fro the first time.

My times for importing 501 buttons_objects.py files were.
- running each as a script 1.9sec
- importing for the first time 1.8sec
- importing a second time (using pyc files) 0.57sec

Also added "bpy" to sys.modules so it can be imported.

source/blender/python/intern/bpy_rna.c

@@ -1526,10 +1526,13 @@ PyObject* pyrna_struct_Subtype(PointerRNA *ptr)
 		- myClass = type(name='myClass', bases=(myBase,), dict={'some':'value'})
 		*/
 		char name[256], *nameptr;
+		const char *descr= RNA_struct_ui_description(ptr);
 
 		PyObject *args = PyTuple_New(3);
 		PyObject *bases = PyTuple_New(1);
 		PyObject *dict = PyDict_New();
+		PyObject *item;
+		
 		
 		nameptr= RNA_property_string_get_alloc(ptr, nameprop, name, sizeof(name));
 		
@@ -1544,6 +1547,12 @@ PyObject* pyrna_struct_Subtype(PointerRNA *ptr)
 		PyTuple_SET_ITEM(args, 1, bases);
 		
 		// arg 3 - add an instance of the rna 
+		if(descr) {
+			item= PyUnicode_FromString(descr);
+			PyDict_SetItemString(dict, "__doc__", item);
+			Py_DECREF(item);
+		}
+		
 		PyTuple_SET_ITEM(args, 2, dict); // fill with useful subclass things!
 		
 		if (PyErr_Occurred()) {
@@ -1552,23 +1561,19 @@ PyObject* pyrna_struct_Subtype(PointerRNA *ptr)
 		}
 		
 		newclass = PyObject_CallObject((PyObject *)&PyType_Type, args);
-		// Set this later
-		
+		Py_DECREF(args);
 
 		if (newclass) {
-			PyObject *rna;
 			RNA_struct_py_type_set(ptr->data, (void *)newclass); /* Store for later use */
 
 			/* Not 100% needed but useful,
 			 * having an instance within a type looks wrong however this instance IS an rna type */
-			rna = pyrna_struct_CreatePyObject(ptr);
-			PyDict_SetItemString(((PyTypeObject *)newclass)->tp_dict, "__rna__", rna);
-			Py_DECREF(rna);
+			item = pyrna_struct_CreatePyObject(ptr);
+			PyDict_SetItemString(((PyTypeObject *)newclass)->tp_dict, "__rna__", item);
+			Py_DECREF(item);
 			/* done with rna instance */
 		}
 		
-		Py_DECREF(args);
-		
 		if (name != nameptr)
 			MEM_freeN(nameptr);
 	}