a messy try of implementing a plugin system for code generator

Manual:
 *run a build
 *look into tool/generate_builtin.py
 *seach opcua.c for "Hello"

tool/plugin_Node.py

@@ -0,0 +1,11 @@
+from __future__ import print_function
+
+def setup():
+	config = dict()
+	config["pluginType"] = "structuredObjectCreation";
+	config["tagName"] = "Node";
+	return config
+
+def createElement(element, fc, fh):
+	print("/* Hello from plugin */", end='\n', file=fc)
+	return "continue"