Updated CMS node and blog to remove extension data.

Comments: minor update.

Updated CMS_NODE_STORAGE_I API.
Delete a node using a node as formal parameter instead of node id.
Clean code and update log information.

Added precondition to delete node to accept nodes with a valid a id.

Added missing assertions tag names.

modules/node/persistence/cms_node_storage_extension.e

@@ -49,6 +49,13 @@ feature -- Persistence
 			end
 		end
 
+	delete_node (a_node: CMS_NODE)
+			-- remove node extensions.
+		require
+			a_node_accepted: is_accepted (a_node)
+		deferred
+		end
+
 feature {NONE} -- Persistence implementation
 
 	store (a_node: G)