Added CMS_HOOK_CACHE, and admin cache.

Prepared evolution of feed module, by allowing json object to list feeds locations.
   The associated key will be used to identify the location, and have category filter by location.

src/hooks/cms_hook_core_manager.e

@@ -104,7 +104,6 @@ feature -- Hook: menu_alter
 			end
 		end
 
-
 feature -- Hook: form_alter
 
 	subscribe_to_form_alter_hook (h: CMS_HOOK_FORM_ALTER)
@@ -177,6 +176,29 @@ feature -- Hook: block
 			end
 		end
 
+feature -- Hook: cache
+
+	subscribe_to_cache_hook (h: CMS_HOOK_CACHE)
+			-- Add `h' as subscriber of cache hooks CMS_HOOK_CACHE,
+			-- and response `a_response'.
+		do
+			subscribe_to_hook (h, {CMS_HOOK_CACHE})
+		end
+
+	invoke_clear_cache (a_cache_id_list: detachable ITERABLE [READABLE_STRING_GENERAL]; a_response: CMS_RESPONSE)
+			-- Invoke cache hook for identifiers `a_cache_id_list'.
+		do
+			if attached subscribers ({CMS_HOOK_CACHE}) as lst then
+				across
+					lst as c
+				loop
+					if attached {CMS_HOOK_CACHE} c.item as h then
+						h.clear_cache (a_cache_id_list, a_response)
+					end
+				end
+			end
+		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)"