refresh tokens (jeremyephron#50)

* refresh token if expired on access to service

* add refresh in Message

* update version

case insensitive header check

signature bug fix

Merge branch 'master' of https://github.com/jeremyephron/simplegmail

Merge branch 'master' of https://github.com/jeremyephron/simplegmail

Merge pull request jeremyephron#38 from jeremyephron/spam_trash_bugfix

used include_spam_trash

Gmail: creds_file param reversion fix

Merge branch 'roib20-patch-1'

fixed query

fixed query