Trying out the Unlicense

The [Unlicense](http://unlicense.org/) text seems to be a great model for putting software into the public domain. It is inspired by one of the most successful public domain software projects of all time, SQLite (which is probably both in your web browser and your cell phone.) It also seems to be used by a non-trivial amount of software.

Let's discuss using this not only for hmda-tools, but for more software in the future.