Add as package

Here's a naive implementation for adding as package based on moduleType, per issue #1.

There a few unit tests added, but no acceptance tests. Variable/string names will probably change based on final version of moduleType in bower.json spec. 

I'm also not sure yet how yall want to handle location/main, looks like there was some considerable discussion on this.

But perhaps this is can be an initial strawman. (it's actually something I need for my current projects anyway).