[Imap-protocol] literal usage

[Bill Janssen]

> As a general rule, one (and only one) space separates tokens in IMAP. 

In my server implementation, I tried to follow the old rule of "be
liberal in what you accept, and strict in what you provide."  So
though arguments to IMAP commands are strictly speaking separated by
exactly one space, I accept any run of whitespace in place of that
single space.  I'm speaking only of top-level arguments to a command,
of course.

Bill