Windows recipes and appveyor CI.

NOTE: GEOS takes >30mn to build, and therefore will fail whenever it is updated. To get around this, I've build GEOS on my own machine and uploaded manually. Everything else should work swimmingly. :smile: 

This is for 32-bit Windows only. 64 bit building hasn't yet been tested.
How about https://github.com/SciTools/conda-recipes-scitools/blob/master/iris/build.sh#L6?