Support custom filename encoding option

[thenickdude]

Supports filenames with non-UTF8 encodings during extract() by adding a "filenameEncoding" option.

If you use "binary" as the filename encoding, then it's even possible to recover the exact original filenames from the tar, using Buffer.from(filename, "binary") in the client code. (This is important for my use-case, where I need to verify the contents of a tar against the filesystem, so the filenames I get from the tar need to be identical to those that were originally on disk!)

[piranna]

@thenickdude, could you be able to fix the conflicts with master branch, please? :-) After that I'll merge the pull-request.

[thenickdude]

I've rebased now!

[piranna]

Merged :-)