Hi. I've attached some patches for a golang importer

To use:
1. (load "golang.scm")
2. (define gopkg (make-go-package go-name*))
3. (package-sexp gopkg)
;; go-name looks like "golang.org/auth/pkg"

;; TODO
1. reliant on github urls
2. extract license
3. Recursive?

Suggestions welcome

Thanks,
Amar