http://stackoverflow.com/q/28923997 and various other SO questions point out that imaplib's _MAXLINE value is a bit behind the times. Fine for 1997, when people had 10MB mailbox quotas, not so fine for the age of gmail.

I'm tired of seeing those questions, so the attached patch increases the limit without abolishing it completely.

There are also other issues in imaplib, but I fix just this one now, to test the waters so to speak.

FWIW, I've signed the contributor form, just in case.