Add a history section to the bottom of the document

Adds to the bottom:

```
History
August 19, 2013. First published.

December 12, 2013. Rewrote the introduction. Removed “However”s in the suggested language.
Added sections on determining IP status, that data is not copyrightable as such, and that this
applies to software as well as data. Corrected typos. Added OKFN (removed the asterisk), EFF,
and PK.
```

As in #9, using the date that we plan to first publicize the update.