plugins: python-renderer: Add license and doxygen

plugins/python-renderer/src/plugin-main.c

@@ -1,3 +1,30 @@
+/*
+ * GDSII-Converter Python Plugin
+ * Copyright (C) 2019  Mario Hüttel <mario.huettel@gmx.net>
+ *
+ * This file is part of GDSII-Converter.
+ *
+ * GDSII-Converter is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * GDSII-Converter is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GDSII-Converter.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @defgroup python-plugin Python Plugin for External Renderer
+ * @ingroup plugins
+ * This is a plugin for calling an external python script as renderer
+ * @addtogroup python-plugin
+ * @{
+ */
+
 #include <stdio.h>
 #include <glib.h>
 #include <unistd.h>