Implemented a basic block caching system.

- for block {block_id}, to have a cache with 3600 seconds of expiration,
    declare in the cms.ini
     [blocks]
     {block_id}.expiration=3600

Added support for size in feed aggregation with new field "size"

modules/feed_aggregator/feed_aggregation.e

@@ -17,6 +17,7 @@ feature {NONE} -- Initialization
 			create {ARRAYED_LIST [READABLE_STRING_8]} locations.make (0)
 			expiration := 60*60
 			description_enabled := True
+			size := 10
 		end
 
 feature -- Access
@@ -28,6 +29,9 @@ feature -- Access
 			-- Suggested expiration time in seconds (default: 1 hour).
 			-- If negative then never expires.
 
+	size: INTEGER
+			-- Number of entries to display per page.
+
 	description: detachable IMMUTABLE_STRING_32
 			-- Optional description.
 
@@ -58,6 +62,12 @@ feature -- Element change
 			expiration := nb_seconds
 		end
 
+	set_size (nb: INTEGER)
+			-- Set `size' to `nb'.
+		do
+			size := nb
+		end
+
 	set_description_enabled (b: BOOLEAN)
 			-- Set `description_enabled' to `b'.
 		do