Initial Import: Database transaction handling.

Initial Import: Error handling using ewf error library.
Added a CMS_ERROR_FILTER as part of registered filters of CMS_SERVICE

persistence/implementation/common/database/error/database_error.e

@@ -0,0 +1,23 @@
+note
+	description: "Error from database"
+	date: "$Date: 2013-08-08 16:39:49 -0300 (ju. 08 de ago. de 2013) $"
+	revision: "$Revision: 195 $"
+
+class
+	DATABASE_ERROR
+
+inherit
+	ERROR_CUSTOM
+
+create
+	make_from_message
+
+feature {NONE} -- Init
+
+	make_from_message (a_m: like message; a_code: like code)
+			-- Create from `a_m'
+		do
+			make (a_code, once "Database Error", a_m)
+		end
+
+end