`make` detects the platform and builds

Addresses #63

This is a pretty naive approach to detecting the platform. On windows it fails outright with a message telling the user to use one of the windows `.mak` files. It maps mac, linux and bsd to the appropriate file and simply has make invoke the correct file.

I also updated the documentation and readme files.

I tested under Mac and Linux -- I would like to ensure windows and sun work properly, but I didn't have a way to test that out today.