hybrid text/binary mount

[DJ Delorie]

> That was the caveat I was pointing out as well -- better the devil
> you ... At least we can now control the behaviour in two predictable
> ways -- mount and explicit binary/text mode I/O.

How about, instead of "auto" we call it "mixed" - read in text mode,
write in binary mode?  A text-mode read will handle unix-style text
files properly anyway, but we won't need that complex detection code.