a locker-package allocation algorithm

Simple as can be.

I don't actually use this library for anything yet, I wrote it in response to an interview question. I only had like 30 minutes to answer the question so I used a very simplified approach, and it got me thinking about exactly how complex a real world solution to the problem would need to be in order to be at all useful, and this is what I came up with.

Check it out and run go test, or import it into your existing go project.