add buildenv to interactively build program

- added s3cmd to upload archives
- to upload archives, you need to have the following env variables setup in
  the host
  - AWS_ACCESS_KEY
  - AWS_SECRET_KEY
  - AUTOPARTS_HOST
  - AUTOPARTS_BUCKET
setup env before running the shell
Merge pull request #74 from nitrous-io/dockerbuild

add buildenv to interactively build program