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/site/modules/messaging/files/scss/messaging.scss

@@ -0,0 +1,6 @@
+.messaging-box {
+	fieldset {
+		overflow:scroll; 
+		height:250px;
+	}
+}