Added specific Windows instructions
Added specific Windows instructions

As requested I’ve provided the steps I used to get glumpy running on a Windows x64 system using Python 3. Note that not all of the example code works after this (still missing something?), but glumpy base functionality works. I've tried my best at formatting this cleanly, but I'm not really familiar with the markup used here. Feel free to clean it up if you want.
glumpy/glumpy,glumpy/glumpy