Extensions need updated directory paths

[Robert Scheller]

Dear extension developers:

If you have included a directory path somewhere in your code (e.g., '\necn\necn-succession-log.txt'), it should be updated with Path.Combine for LINUX compatibility:

https://docs.microsoft.com/en-us/dotnet/api/system.io.path.combine?view=netframework-4.7.2

Thanks!

Rob