- added experimental support for Loewe / Hisense 2017 servicelist.db

file format
- show error message when trying to open a .zip file that doen't contain
  the expected files of a Samsung J series or Toshiba .zip channel list
- show error message when trying to open a broken .zip file, which is
  most likely caused by exporting to a USB stick formatted with NTFS
- allow changing the "crypt" flag for Samsung .scm lists
- iterating through loaders supporting a file extension till one can read the file

source/ChanSort.Loader.Panasonic/Serializer.cs

@@ -339,6 +339,11 @@ namespace ChanSort.Loader.Panasonic
         {
           RepairCorruptedDatabaseImage(cmd);
           InitCharacterEncoding(cmd);
+
+          cmd.CommandText = "SELECT count(1) FROM sqlite_master WHERE type = 'table' and name in ('svl', 'tsl')";
+          if (Convert.ToInt32(cmd.ExecuteScalar()) != 2)
+            throw new FileLoadException("File doesn't contain the expected TSL/SVL tables");
+
           this.ReadChannels(cmd);
         }
       }