Hi!
Just wanted to post this incase anyone else runs into the same issue with building aerogear-js. I was previously on an older version of Grunt 0.3.x, and to build Grunt "~0.4.0rc5" is a requirement.
I've created this gist [1] with the steps that I took to get this to build successfully . This might common knowledge to most people but I thought I'd post just in case.