Fixed: show a better error message when nzbdrone port is already in use.

src/NzbDrone.Console/ConsoleApp.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net.Sockets;
 using NLog;
 using NzbDrone.Common.EnvironmentInfo;
 using NzbDrone.Common.Instrumentation;
@@ -18,6 +19,15 @@ namespace NzbDrone.Console
                 LogTargets.Register(startupArgs, false, true);
                 Bootstrap.Start(startupArgs, new ConsoleAlerts());
             }
+            catch (SocketException exception)
+            {
+                System.Console.WriteLine("");
+                System.Console.WriteLine("");
+                Logger.Fatal(exception.Message + ". This can happen if another instance of NzbDrone is already running or another applicaion is using the port assinged to NzbDrone (default: 8989)");
+                System.Console.WriteLine("Press any key to exit...");
+                System.Console.ReadLine();
+                Environment.Exit(1);
+            }
             catch (Exception e)
             {
                 System.Console.WriteLine("");
@@ -25,6 +35,7 @@ namespace NzbDrone.Console
                 Logger.FatalException("EPIC FAIL!", e);
                 System.Console.WriteLine("Press any key to exit...");
                 System.Console.ReadLine();
+                Environment.Exit(1);
             }
 
             Logger.Info("Exiting main.");