The login is root / root.

I will be making a post on how to add other tools like node.js.

In the meanwhile, you can use this image: http://samdecrock.be/wpe-with-tools.img

It contains node.js, git, curl and a bunch of other tools you can use for web development. To expand the file system, follow these instructions: https://raspberrypi.stackexchange.com/a/501/94049