- added "Pooling=False" parameter to all Sqlite connection strings to prevent open file locks after closing the connection and to avoid extreme delays when using CloseAllPools()
- C# code refactoring "using var" instead of "using ( ) { }" where possible
- added round-trip unit test for all loaders to check reordering channels and favorites, saving and reloading
- internal code clean-up regarding different favorite list modes (none vs. flags vs. ordered per source vs. mixed source)
