Added circle.yml
Added possibility to specify PORT
Added heroku build files

Procfile is used directly by heroku,
heroku-pre.sh is used by our buildpack
and must be referenced in heroku config
var PRE_SCRIPT
Client dir can be specified by env var
Added .profile.d script for heroku
Added auto-deployment to heroku
Merge pull request #24 from joozek78/master

CI support