Add ability to deploy npm package (tarball)

See also: https://github.com/strongloop/strong-pm/pull/12
A branch would be masked by a file with the same name. If the problem was reversed the user could prefix the file name with `./`, but I'm not sure how to force the name to be treated as a branch in this case. Names like `deploy`, `test`, `dev`, `src` all seem equally valid as paths and branch names.