mailbox().count() bugfix
label search bugfix

Label search was giving an error when searching with mail(label="foo"):
UID command error: BAD ['Could not parse command']

Gmail seems to want a special name for searching labels:
X-GM-LABELS

@see: https://developers.google.com/gmail/imap_extensions
Merge pull request #18 from carver/master

mailbox().count() bugfix