More special chars in mailbox names

[Ken Murchison]

While looking over bug #3002, 
https://bugzilla.andrew.cmu.edu/show_bug.cgi?id=3002

I started wondering what other special characters we might want to 
allow.  The original authors were more restrictive with GOODCHARS than 
the RFC.  AFAICT the following characters are permitted by RFC 3501 but 
aren't included in GOODCHARS

! # $ & ' ; < > ? [ ^ ` } |


! and ^ have special meaning to Cyrus, so we may not want to add these 
to GOODCHARS.  & and ? might conflict with modified UTF-7 encoding.

Looking back at the list archives, there have been several requests to 
allow ' (single quote) and I'm included to do so.

Does anybody want to make a case for adding more?

Has anybody already added some of these in production without any 
adverse effects?

-- 
Kenneth Murchison
Systems Programmer
Project Cyrus Developer/Maintainer
Carnegie Mellon University