Added url routing for /files/... and /module/{modname}/files/...

Added CMS_HOOK_RESPONSE_ALTER to give a last chance to alter the response before rendering.
   This hook should not be used, when there are other alternative hook that answer the need, but this is proposed for now, as a way to alter response by adding css, js url, ...
Moved blog under official modules folder.
Cleaned theme of demo example project.
Renamed NODE_MODULE as CMS_NODE_MODULE.

src/configuration/cms_default_setup.e

@@ -63,6 +63,14 @@ feature {NONE} -- Initialization
 				-- Can be also used to precise the "From:" value for email.
 			site_email := text_item_or_default ("site.email", "webmaster")
 
+
+				-- Location for public files
+			if attached text_item ("files-dir") as s then
+				create files_location.make_from_string (s)
+			else
+				files_location := site_location.extended ("files")
+			end
+
 				-- Location for modules folders.
 			if attached text_item ("modules-dir") as s then
 				create modules_location.make_from_string (s)

src/configuration/cms_setup.e

@@ -95,6 +95,9 @@ feature -- Access: Theme
 	site_location: PATH
 			-- Path to CMS site root dir.
 
+	files_location: PATH
+			-- Path to public "files" dir.			
+
 	modules_location: PATH
 			-- Path to modules.