Better filetype & auxtype support

[JohnMBrooks]

Ideally retain filetype & auxtype between Mac OS files & ProDOS

And/or allow explicit filetype and auxtype suffix:
PRODOS#FF0000
BIN.AT.2000#062000

-JB
@JBrooksBSI

[mach-kernel]

I think the latter might be a more elegant solution since I think that attempting file kind translations on other systems (e.g. Linux, Windows) might be an exercise, and namely it would be great if we provided a consistent expectation for how Cadius works everywhere. Does the latter sit well with you? 🦄

Sorry for the delay in response, finally just got home stateside this weekend 😄

PS: Some reference docs for OS X: https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/FileSystemDetails/FileSystemDetails.html