Move slugbuilder to deis repo. Create global ENV vars with profile.d/controller_env.sh primarily for use by slugbuilder. opdemand/deis#376
Use /etc/environment instead of /etc/profile.d/controller_env.sh for global vars
Moved .write_file() call inside iteration loop for ENV keys
Merge pull request #47 from tombh/376-move-slugbuilder-hook

Tested, works great. Thanks very much, Tom!