OBJ: remove "experimental" from C++ based importer/exporter, mark Python legacy

By now I'm not aware of any serious regressions or missing functionality
in the C++ based OBJ importer/exporter. They have more features (vertex colors
support), and are way faster than the Python based importer/exporter.

Reviewed By: Thomas Dinges, Howard Trickey
Differential Revision: https://developer.blender.org/D15360

io_scene_obj/__init__.py

@@ -459,11 +459,11 @@ class OBJ_PT_export_geometry(bpy.types.Panel):
 
 
 def menu_func_import(self, context):
-    self.layout.operator(ImportOBJ.bl_idname, text="Wavefront (.obj)")
+    self.layout.operator(ImportOBJ.bl_idname, text="Wavefront (.obj) (legacy)")
 
 
 def menu_func_export(self, context):
-    self.layout.operator(ExportOBJ.bl_idname, text="Wavefront (.obj)")
+    self.layout.operator(ExportOBJ.bl_idname, text="Wavefront (.obj) (legacy)")
 
 
 classes = (