Release 0.1.0

It's about time we cut a release!

As we're using some of the same infrastructure as pandas, their [release checklist](https://github.com/pydata/pandas/wiki/Release-Checklist) is useful as a reference, though GeoPandas should be rather simpler.

One difference is that I will plan on tagging the merge commit of this pull request as the release candidate, and then as 0.1.0 if all goes well.

I'll open a couple remaining issues on [this milestone](https://github.com/kjordahl/geopandas/issues?milestone=1&state=open) and see if we can clear them up in the next day or so, in time for my [SciPy talk](https://conference.scipy.org/scipy2014/schedule/presentation/1674/) on Tuesday.