Deal better with mailing list groups when parsing incoming mail.
Deal better with mailing list groups when parsing incoming mail.

Mailing list groups aren't completely accounted for in Geary (#3713) but in the last commit
I skipped one place they can easily be dealt with.  This takes care of that.

emersion/geary,mjog/geary,glebihan/geary,kyoushuu/geary,AtticHacker/geary,abn/geary,rschroll/geary,tshikaboom/geary,emersion/geary,kpiwko/geary,martinra/geary,aatishnn/geary,mjog/geary,jimbonator/geary,robol/geary,orlandosanchez/geary,orlandosanchez/geary,githubnemo/geary,didrocks/geary,martinra/geary,jimbonator/geary,jimbonator/geary,dominickm/Geary,MohamedIM/geary-unofficial,emersion/geary,tshikaboom/geary,robol/geary,martinra/geary,orlandosanchez/geary,tshikaboom/geary,mjog/geary,AtticHacker/geary,dominickm/Geary,mpdeimos/geary,glebihan/geary,githubnemo/geary,githubnemo/geary,glebihan/geary,robol/geary,geekvigilante/geary,kyoushuu/geary,aatishnn/geary,AtticHacker/geary,aatishnn/geary,rschroll/geary