Specify all configuration settings in config.yml.

* Added README with step-by-step build instructions.
* config.rb substitutes config.yml variables in *.in files.
Bug fixes.
Configure Apache and Passenger.
Fix passenger filename.
Start the API container with supervisor, running postgres & apache2.
Reduce commands in Dockerfiles to stay under the 42-layer limit for AUFS
  (https://github.com/dotcloud/docker/issues/1171)
Use supervisord to start postgres + apache2 when the api
container is launched.

Move generated files to an api/generated directory for
easier ignoring.
We don't use the bootstrap-rails gem, and it does not exist anymore.
Fix deprecation warning:

  do not use ActionController::UnknownAction
Rename config.yml to config.yml.example (easier to keep real configuration
settings out of the repo)
Allow up to 10 levels of nesting for variable substitution in config.rb
Style improvements -- rubocop
We want to be able to handle naked

  false

in config.rb's variable substitution.
Copied Apache vhost config from qr1hi.
Merge branch '1578-api-server-in-docker' of git.clinicalfuture.com:arvados into 1578-api-server-in-docker

Conflicts:
	docker/config.rb
Set nameservers at config time.
Merge branch '1578-api-server-in-docker'