[MERGE] An SMTPConnection class for bzrlib

[Aaron Bentley]

Aaron Bentley has voted +0.
Status is now: Semi-approved
Comment:
The error handling isn't right; it shouldn't be raising 
BzrCommandErrors, because it's not UI code.  I think it would make sense 
to just let the smtplib errors pass through.

Also, our style is to import modules rather than functions:
e.g. from email import Utils

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070619161158.GA14616%40chistera.yi.org%3E