Update Procfile to use Makefile to start.
Force-add Makefile.vars to make it run on heroku using env var instead.
Make init.coffee generate heroku config:set lines
Better default make task selection based on env vars.

So we don't have to add Makefile.vars just to make it run on Heroku.
Uses env vars to siginify instead.
[spotify] Uses lodash instead of underscore.