- replaced misuse of "FileLoadException" with a custom LoaderException to handle file loading issues with better continue/fail logic
- removed "Save As" and replaced it with "Convert list" menu item that shows information on how to use a reference list instead of direct conversion
- added support for Hisense .csv files with 6 columns including "channel number" and "LCN"
- using separate lists for DTV, Radio and Data, which all start with 1
- improved reference list channel matching: if multiple channels match the same name, then the candidates are narrowed
down by service type (TV/radio/data - if known), case sensitivity (upper/lowercase), encryption (unencrypted first)
