"jackup" not picking up packages in the local packages directory

[imnaseer]

To reproduce on a debian box:

Create a new narwhal package, f.ex: tusk init my-project

Create a local packages directory inside my-project and create a new
package inside that packages directory, f.ex:

mkdir packages && cd packages && tusk init my-local-package

Add lib/foo-module.js file inside my-local-package/lib directory.

Now add a test.js file inside my-project/lib directory and require
foo-module defined in my-local-package.

If you invoke test.js using narwhal then everything works fine. If
instead you invoke test.js using jackup, the system is unable to load
the foo-module.