docker.run: optionally demux stream

In order to be able to easily retrieve demuxed std{out,err},
one can now pass an array of two streams as the stream input.

Resolves #58.
docker.run: emit immediate results

In order to have a better way hooking into the immediate steps of docker.run,
emit the resulting container, stream and data via an event emitter that is
returned from the function.
Merge pull request #59 from srijs/patch-1

docker.run: optionally demux stream
Merge branch 'patch-2' of github.com:srijs/dockerode into srijs-patch-2

Conflicts:
	lib/docker.js