v0.9.6 release

[shoyer]

I plan to issue this in within the next few days, after merging #1260 (Rasterio support) and #1439 (pydap fix). Let me know if there's anything else critical to get in.

CC @pydata/xarray

[shoyer]

Done! See http://xarray.pydata.org/en/stable/whats-new.html

[fmaussion]

Any roadmap for the next major release? Will this be a 0.10.0 then?

[shoyer]

So far, I've been saving major version numbers for breaking changes. But they are also useful to signal large advances in functionality, even if they don't break compatibility.