examples: Add a non-trivial "library" example

This example includes a build process which includes:

  * testing multiple modules
  * building a "test entry" via multiple "test" files
  * including 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
Merge pull request #38 from stephenmathieson/add/library-example

examples: Add a non-trivial "library" example