Merge pull request #11 from sritchie/master

STARTTLS support.  Works for Gmail, closing #7 & #11.
Add main back.
Tweak ssl/tls settings for better defaults and more flexibility.
Add docs for SSL/TLS.
Add Sam as contributor.
Clarify docs.
Add lein example.  Closes #12.
Release 1.7.0.
Bump 1.8-SNAPSHOT.
Ignore lein artifacts.
Clarify platform reqs.
Whitespace fixes.
Add another arity to send-message, and make subject and body optional.

Subject and body default to the empty string.
Fixed port determination for smtp sending.
added support for different multipart types
Merge pull request #14 from joegallo/master

whitespace and a new arity for send-message.
Add repl-utils dep to have a dormant show laying around.
Add test for smtp args.
Merge branch 'smtp-tests'
Merge branch 'master' of https://github.com/drewr/postal

Conflicts:
	src/postal/smtp.clj