[update] nodejs image to latest stable version.

Besides that, it now inherits from debian:jessie image, which reduces it's
size and the number of processes running.
[update] nodejs image to latest unstable version.

Besides that, it now inherits from debian:jessie image, which reduces it's
size and the number of processes running.
[fix] Missing system dep.
[update] Spidermonkey image inherit from debian:jessie.