Display an error message in command line on app domain restart

With dynamic compilation, it is sometimes necessary to restart the AppDomain.
In the command line scenario, instead of restarting the appdomain, we throw
an exception with an descriptive error message.

--HG--
branch : dev

src/Orchard/Commands/CommandHostEnvironment.cs

@@ -2,9 +2,16 @@ using System;
 using System.Linq;
 using System.Web.Hosting;
 using Orchard.Environment;
+using Orchard.Localization;
 
 namespace Orchard.Commands {
     public class CommandHostEnvironment : IHostEnvironment {
+        public CommandHostEnvironment() {
+            T = NullLocalizer.Instance;
+        }
+
+        public Localizer T { get; set; }
+
         public bool IsFullTrust {
             get { return AppDomain.CurrentDomain.IsFullyTrusted; }
         }
@@ -18,11 +25,11 @@ namespace Orchard.Commands {
         }
 
         public void RestartAppDomain() {
-            //Don't restart AppDomain in command line environment
+            ResetSiteCompilation();
         }
 
         public void ResetSiteCompilation() {
-            //Don't restart AppDomain in command line environment
+            throw new OrchardCoreException(T("A change of configuration requires the application to be restarted. Running the command again usually solves this problem."));
         }
     }
 }

src/Orchard/Environment/Extensions/Loaders/ReferencedExtensionLoader.cs

@@ -45,6 +45,7 @@ namespace Orchard.Environment.Extensions.Loaders {
                         Logger.Information("ExtensionRemoved: Deleting assembly \"{0}\" from bin directory (AppDomain will restart)", moduleName);
                         File.Delete(_virtualPathProvider.MapPath(assemblyPath));
                     });
+                ctx.RestartAppDomain = true;
             }
         }