Better handling of environment variables

Use runit's built in mechanism for handling environment variables, which is set by using the env parameter in the runit_service definition.

It puts each environment variable in a directory (one file per variable) which is interpreted when the service starts. The default location is /etc/service/hubot/env/. This handles numeric values, although you need to quote them in your recipe, and values with spaces.
For Example:
node.set['hubot']['config'] = {
  "PORT" => "9000",
  "GTALK_PRESENCE" => "Echoing to campfire"
}

For more info on chpst -e see http://smarden.org/runit/chpst.8.html