Add resource dependencies to jars

I was working on this on Foursquare's fork of commons and Benjy said I should send the request here for review.

We want to be able to include resources in jar files. The resource functionality exists but is ignored during the jvm binary command. This pull request adds that functionality along with the ability to specify a "prefix" for a set of resources. The prefix, defaulting to the pants build root, is removed from the resource paths when added them to the jar.