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/Model/EpisodeStatusType.cs

@@ -5,7 +5,7 @@
         /// <summary>
         ///   Episode has not aired yet
         /// </summary>
-        NotAired ,
+        NotAired,
 
         /// <summary>
         /// Episode is ignored
@@ -16,12 +16,22 @@
         /// Episode has aired but no episode
         /// files have avilable
         /// </summary>
-        Missing ,
+        Missing,
         
         /// <summary>
         /// Episode is being downloaded
         /// </summary>
-        Downloading ,
+        Downloading,
+
+        /// <summary>
+        /// Episode has been downloaded and is unpacking (_UNPACK_)
+        /// </summary>
+        Unpacking,
+
+        /// <summary>
+        /// Episode has failed to download properly (_FAILED_)
+        /// </summary>
+        Failed,
 
         /// <summary>
         /// Episode is present in disk

NzbDrone.Core/Model/PostDownloadStatusType.cs

@@ -0,0 +1,25 @@
+namespace NzbDrone.Core.Model
+{
+    public enum PostDownloadStatusType
+    {
+        /// <summary>
+        ///   Unknown (Default)
+        /// </summary>
+        Unknown = 0,
+
+        /// <summary>
+        ///   Unpacking
+        /// </summary>
+        Unpacking = 1,
+
+        /// <summary>
+        /// Failed
+        /// </summary>
+        Failed = 2,
+
+        /// <summary>
+        /// Processed
+        /// </summary>
+        Processed = 3
+    }
+}