(feature) Convert a message to an event or task

Resolves #1722

UI/WebServerResources/js/Mailer/Message.service.js

@@ -362,6 +362,15 @@
     });
   };
 
+  /**
+   * @function $plainContent
+   * @memberof Message.prototype
+   * @returns the a plain text representation of the subject and body
+   */
+  Message.prototype.$plainContent = function() {
+    return Message.$$resource.fetch(this.$absolutePath(), 'viewplain');
+  };
+
   /**
    * @function addTag
    * @memberof Message.prototype