Improved error library by refactorying the sync as two way propagation.

Now one can setup error handler propagation in one way, or two way (sync).
The "reset" applies in both way, even if this is a one way propagation to fit current existing usage.
Added optional id for the error handlers.
Feature renaming according to design changes.
Added related autotest cases.

library/utility/general/error/package.iron

@@ -5,11 +5,13 @@ project
 	error = "error.ecf"
 
 note
---	title: 
---	description: 
---	tags: 
---	license: 
---	copyright: 
---	link[doc]: "Documentation" http:// 
+	title: Error framework
+	description: "[
+		Errors and associated handler, to manage errors and also provides a way to synchronize one or many error handlers. 
+		This is convenient to propagate error from a layer to another without adding unwanted dependencies.
+	tags: error
+	license: Eiffel Forum License v2
+	copyright: Jocelyn Fiat, Eiffel Software and others.
+	link[license]: http://www.eiffel.com/licensing/forum.txt
 
 end