New: Parse existing subtitles and extra files

Towards #459

src/NzbDrone.Core/Configuration/ConfigService.cs

@@ -202,6 +202,13 @@ namespace NzbDrone.Core.Configuration
             set { SetValue("EnableMediaInfo", value); }
         }
 
+        public string ExtraFileExtensions
+        {
+            get { return GetValue("ExtraFileExtensions", ""); }
+
+            set { SetValue("ExtraFileExtensions", value); }
+        }
+
         public bool SetPermissionsLinux
         {
             get { return GetValueBoolean("SetPermissionsLinux", false); }

src/NzbDrone.Core/Configuration/IConfigService.cs

@@ -35,6 +35,7 @@ namespace NzbDrone.Core.Configuration
         bool SkipFreeSpaceCheckWhenImporting { get; set; }
         bool CopyUsingHardlinks { get; set; }
         bool EnableMediaInfo { get; set; }
+        string ExtraFileExtensions { get; set; }
 
         //Permissions (Media Management)
         bool SetPermissionsLinux { get; set; }