Use Concierge in mailgun controller
Setup backend for replies to notification emails
Use Mail::Address to parse email and name from email addresses
Setup Conversation Mailer
Use condensed FactoryGirl syntax

FactoryGirl.create -> create
FactoryGirl.build 	 -> build
Add Conversation#mailbox/.match_mailbox

Both Account and Conversation now have #mailbox methods:
@account.mailbox #=> 'slug@helpful.io' (Mail::Address object)
@conversation.mailbox #=> 'slug+number@helpful.io' (Mail::Address object)
And .match_mailbox and .match_mailbox! (raise exception if not found) methods which try to match a string back to the Account/Conversation.
Update Concierge to support Conversation#mailbox addresses
After new reply stay in the conversation view
Use params[] instead of params.fetch()
Set a sensible default INCOMING_EMAIL_DOMAIN.
Merge branch 'master' into pr/56