A few suggestions for project documentation

Hi Sonia,

Thanks for adding a tag. :-)

Just a few tweaks:

* I switched your Changelog to Markdown and added a second-level header (`##`) for the version line
* Included is my default contributing document to help people avoid import path issues. Feel free to do whatever you like with it.
* I added a link to the GoDoc documentation, we are working a nice badge icon but it's not available quite yet. https://github.com/garyburd/gddo/pull/112

Also a few suggestions:

* Without a license nobody has the right to use your software. Please [choose a license](http://choosealicense.com/) and place it in a file called LICENSE with your Copyright.
* I'd recommend using a 3 element tag in the future (eg. v0.2.0). I'm just being picky.
* GitHub supports a Markdown extension for tables, which you might find easier to work with.
* Usually Changelogs are just about the history of your project.

Thanks for contributing to the Go community. Now I better go clean up some of my old Go projects. :-)

Nathan.