Unclutter graphics package scope.
Moved some import statements from "graphics" package to "viewer" module.
It also avoid systematic import of everything in graphics when we only need one submodule.

<?xml version='1.0' encoding='utf-8'?>
<BaseParams xmlns:xsd="http://www.w3.org/2001/XMLSchema" IEC_Channel="0" Name="py_ext_0"/>