Redesigned hooks system (moving from CMS_RESPONSE to CMS_API).

Indeed, hooks does not require RESPONSE interface,
   and should be setup before, at the system level (i.e CMS_API)
Added exportation solution via CMS_HOOK_EXPORT.
Updated blocks settings for demo example project.

src/hooks/export/cms_export_json_utilities.e

@@ -0,0 +1,35 @@
+note
+	description: "[
+			Usefull routines to export to JSON.
+		]"
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	CMS_EXPORT_JSON_UTILITIES
+
+feature -- Access
+
+	put_date_into_json (dt: detachable DATE_TIME; a_key: JSON_STRING; j: JSON_OBJECT)
+		local
+			hd: HTTP_DATE
+		do
+			if dt /= Void then
+				create hd.make_from_date_time (dt)
+				j.put_integer (hd.timestamp, a_key)
+			end
+		end
+
+	json_to_string (j: JSON_OBJECT): STRING
+		local
+			pp: JSON_PRETTY_STRING_VISITOR
+		do
+			create Result.make_empty
+			create pp.make (Result)
+			j.accept (pp)
+		end
+
+note
+	copyright: "2011-2015, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+end