closes #319 * Make default node-env use alpine, and support separate debian env. List envs in documentation. * Copy ONBUILD base image commands into node Dockerfiles * Copy more commands from onbuild image * Tidy dockerfiles
closes #319 * Make default node-env use alpine, and support separate debian env. List envs in documentation. * Copy ONBUILD base image commands into node Dockerfiles * Copy more commands from onbuild image * Tidy dockerfiles