Improved node management.

- List node by node types
- fixed the trash/restore/delete workflow
Added messaging module to send message to cms users (by email for now).
Added early protection for cache, export and import functionalities.

examples/demo/roc.cfg

@@ -23,6 +23,7 @@
 		"files": 			{ "location": "../../modules/files" },
 		"custom_block": 	{ "location": "../../modules/custom_block" },
 		"wikitext": 		{ "location": "../../modules/wikitext" },
+		"messaging": 		{ "location": "../../modules/messaging" },
 		"comments": 		{ "location": "../../modules/comments" }
 	}
 }