new way for entering directory names

[Michael Sobolev <mss@transas.com>]

Hello!

I added a new function to boxes.c file: enterDirBox.  And modified
choose_medium.c file to make use of this function.  Only choose_archive_dir
function uses this new way of entering directory names.  Could everybody please
check whether it works fine?  (It works for me, but this may be an ideal case :)

Regards,

--
Mike