Anaconda

I am using the continuum.io anaconda python distribution and I this was my fix to have Shapely work with it. The anaconda distribution does not currently ship with gdal and libgeos; however, I notices continuum.io is hosting the libraries and after installing anaconda you can run

> conda install gdal
> conda install geos

+ the changes I made at least on Mac OSX

This is my first attempt at doing a pull request with git, so if I have violated any etiquette let me know, Thanks