correct fix for bug #23871, __main__ module was being overwritten in nested functions, so on returning from calling operators the __main__ module could be cleared and imported modules turn into None

calling
  bpy.ops.wm.read_factory_settings()
... would clear a scripts namespace if running directly, not in a module.


Fix by backing up and restoring the __main__ module.

Also found BKE_reportf wasnt printing all reports in background mode as BKE_report() was doing.

source/blender/python/generic/py_capi_utils.h

@@ -39,4 +39,7 @@ const char *	PyC_UnicodeAsByte(PyObject *py_str, PyObject **coerce); /* coerce m
 /* name namespace function for bpy & bge */
 PyObject *		PyC_DefaultNameSpace(const char *filename);
 void			PyC_RunQuicky(const char *filepath, int n, ...);
+
+void PyC_MainModule_Backup(PyObject **main_mod);
+void PyC_MainModule_Restore(PyObject *main_mod);
 #endif // PY_CAPI_UTILS_H