Extracted page support from cms_node_module, and add a proper CMS_PAGE_MODULE.

- now, the CMS_PAGE_MODULE has to be declared in the related CMS_SETUP via CMS_EXECUTION.
   (See demo for example)

Improved the export facilities.
  Implemented blog and page export.
Added import facilities.
  Implemented blog and page import.

Improved node revision web interface (allow to edit a past revision, in order to restore it as latest revisionm i.e current).
Removed specific tag from blog module, and reuse the taxonomy module for that purpose.

Added WIKITEXT module that provide a WIKITEXT_FILTER, so now we can have wikitext content.
   - for now, no support for wiki links such as [[Foobar]].

modules/admin/cms_admin_module.e

@@ -58,6 +58,7 @@ feature -- Access: router
 
 			l_admin_cache_handler: CMS_ADMIN_CACHE_HANDLER
 			l_admin_export_handler: CMS_ADMIN_EXPORT_HANDLER
+			l_admin_import_handler: CMS_ADMIN_IMPORT_HANDLER
 
 			l_uri_mapping: WSF_URI_MAPPING
 		do
@@ -89,6 +90,10 @@ feature -- Access: router
 			create l_admin_export_handler.make (a_api)
 			create l_uri_mapping.make_trailing_slash_ignored ("/admin/export", l_admin_export_handler)
 			a_router.map (l_uri_mapping, a_router.methods_get_post)
+			
+			create l_admin_import_handler.make (a_api)
+			create l_uri_mapping.make_trailing_slash_ignored ("/admin/import", l_admin_import_handler)
+			a_router.map (l_uri_mapping, a_router.methods_get_post)
 
 			create l_user_handler.make (a_api)
 			a_router.handle ("/admin/add/user", l_user_handler, a_router.methods_get_post)
@@ -118,7 +123,9 @@ feature -- Security
 			Result.force ("admin core caches")
 			Result.force ("clear blocks cache")
 			Result.force ("admin export")
+			Result.force ("admin import")
 			Result.force ("export core")
+			Result.force ("import core")
 		end
 
 feature -- Hooks
@@ -154,6 +161,9 @@ feature -- Hooks
 
 					-- Per module export permission!
 				create lnk.make ("Export", "admin/export")
+				admin_lnk.extend (lnk)
+					-- Per module import permission!
+				create lnk.make ("Import", "admin/import")
 				admin_lnk.extend (lnk)
 			end
 		end