Added progress messaging, using info logging

Also extension methods for complete and failed (for coloured UI messaging)

NzbDrone.Api/ProgressMessaging/ProgressMessageResource.cs

@@ -0,0 +1,12 @@
+using System;
+using NzbDrone.Api.REST;
+
+namespace NzbDrone.Api.ProgressMessaging
+{
+    public class ProgressMessageResource : RestResource
+    {
+        public DateTime Time { get; set; }
+        public String CommandId { get; set; }
+        public String Message { get; set; }
+    }
+}