fixed service registration for event handlers and executors.

NzbDrone.Common/Messaging/MessageExtensions.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace NzbDrone.Common.Messaging
+{
+    public static class MessageExtensions
+    {
+        public static string GetExecutorName(this Type commandType)
+        {
+            if (!typeof(ICommand).IsAssignableFrom(commandType))
+            {
+                throw new ArgumentException("commandType must implement IExecute");
+            }
+
+            return string.Format("I{0}Executor", commandType.Name);
+        }
+    }
+}