Version 2: Best practices around licensing of open government data

This project is a document containing best practices language for government agencies to use in making clear that they are publishing **license-free data**.

This pull request takes the original **[version 1](http://razor.occams.info/pubdocs/2013-08-19_license_free.pdf)** of this document, released on August 19, 2013, and makes the following (relatively minor) changes:

* An [extended](https://github.com/unitedstates/licensing/commit/b148eb7aac9608c05d6a5fb914c344a605e0b1b2) and [rewritten](https://github.com/unitedstates/licensing/commit/0e1045608608479495ea56ee70e11f98948e19ca) introduction.
* Notes that these principles and the use of the CC0 license [apply equally well to software](https://github.com/unitedstates/licensing/commit/b0a20cb2e1e51fe534ea34a17e26e127fcaf46a8).
* Explicitly notes that [not all data is copyrightable](https://github.com/unitedstates/licensing/commit/125ca4a40b21f126acc379624658ceaa8099ce83).
* States that it's [incumbent on the agency](https://github.com/unitedstates/licensing/commit/d279af48559c6b8896bb3342d1a8220f4eed976f) to determine the intellectual property status of the open data it publishes. (Small clarification [about unclear situations](https://github.com/unitedstates/licensing/commit/96c62f4b8ae0bc5a18fc767617cfc8ef86d53137).)
* Clarifies the suggestion to [openly license non-governmental contributions](https://github.com/unitedstates/licensing/commit/1d08da93742d9930246f80cd62b52602243d9270) when mixed in with governmental publication.
* Mention [Project Open Data](http://project-open-data.github.io/) as a user of CC0 for mixed content data.
* [Tweak some However's](https://github.com/unitedstates/licensing/commit/491c51b6d0acc39f6bcb1d4de2e7240e2b36154b) in the license text (non-substantive).
* [Some small legal tweaks](https://github.com/unitedstates/licensing/pull/3/files) proposed by @thisisparker from the EFF, and [modified slightly](https://github.com/unitedstates/licensing/pull/8/files) after subsequent [dialogue below](https://github.com/unitedstates/licensing/pull/1#issuecomment-28348384).

#### [Read version 2 in full here.](https://github.com/unitedstates/licensing/blob/v2/index.md#open-government-data-best-practices-language-for-making-data-license-free)

If merged, the text will replace the v1 document currently showing at [theunitedstates.io/licensing](http://theunitedstates.io/licensing).

**If you or your organization would like to sign on to this document**, please comment here saying so, along with whether or not you are signing on your organization's behalf. I'll add your name/org/link to the bottom of the document before merging.