examples: Add a non-trivial "library" example

This example includes a build process which:

  * tests multiple modules
  * builds a "test entry" via multiple "test" files
  * includes an npm package (npm/node-semver)

Had an example like this been present when I was figuring out how to
use this tool, tons of time would have been saved :p  Hopefully I can 
save that time for someone else...