Added two new Episode Statuses - Unpacking and Failed.

Tests added to support new Statuses.
PostDownloadScanJob will update PostDownloadStatus for failed or unpacking.
ImportFile will set the PostDownloadStatus to Processed when added to the database.

NzbDrone.Core/Datastore/Migrations/Migration20111011.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Data;
+using Migrator.Framework;
+
+namespace NzbDrone.Core.Datastore.Migrations
+{
+
+    [Migration(20111011)]
+    public class Migration20111011 : Migration
+    {
+        public override void Up()
+        {
+            Database.AddColumn("Episodes", "PostDownloadStatus", DbType.Int32, ColumnProperty.Null);
+        }
+
+        public override void Down()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}