Added revisions support to node management.

Updated node extension implementation.
Updated known permissions for node module.
Improved code for node storage extension , in preparation to code factorization.
Ensured that author is updated when saved.

modules/node/handler/node_view_response.e

@@ -36,6 +36,9 @@ feature -- Access
 
 	node: detachable CMS_NODE
 
+	revision: INTEGER_64
+			-- If not zero, about history version of the node.
+
 feature -- Element change
 
 	set_node (a_node: like node)
@@ -43,18 +46,22 @@ feature -- Element change
 			node := a_node
 		end
 
+	set_revision (a_rev: like revision)
+		do
+			revision := a_rev
+		end
+
 feature -- Execution
 
 	process
 			-- Computed response message.
 		local
-			b: STRING_8
+			b: detachable STRING_8
 			nid: INTEGER_64
 			l_node: like node
 		do
 			l_node := node
 			if l_node = Void then
-				create b.make_empty
 				nid := node_id_path_parameter (request)
 				if nid > 0 then
 					l_node := node_api.node (nid)
@@ -67,8 +74,16 @@ feature -- Execution
 				then
 					l_manager.append_html_output_to (l_node, Current)
 				end
+			elseif revision > 0 then
+				set_main_content ("Missing revision node!")
 			else
-				set_main_content ("Missing node")
+				set_main_content ("Missing node!")
+			end
+			if revision > 0 then
+				add_warning_message ("The revisions let you track differences between multiple versions of a post.")
+			end
+			if l_node /= Void and revision > 0 then
+				set_title ("Revision #" + revision.out + " of " + html_encoded (l_node.title))
 			end
 		end