part 2 basedoc: move BaseDoc.py to /gen/plug/docgen and add /gen/plug/docbackend

that was missing in part 1 
 Still to come: makefiles and splitting new basedoc.py in small files


svn: r12591

src/PluginUtils/_GuiOptions.py

@@ -1315,9 +1315,9 @@ class GuiStyleOption(GuiEnumeratedListOption):
         """The user has clicked on the 'Edit Styles' button.  Create a
         style sheet editor object and let them play.  When they are
         done, update the displayed styles."""
-        import BaseDoc
+        from gen.plug.docgen import StyleSheetList
         from ReportBase._StyleEditor import StyleListDisplay
-        style_list = BaseDoc.StyleSheetList(self.__option.get_style_file(), 
+        style_list = StyleSheetList(self.__option.get_style_file(), 
                                             self.__option.get_default_style())
         StyleListDisplay(style_list, None, None)