Windows support that stub out the einhorn/systemd functionality

Hi, Carl!
First of all - thanks for the great framework!
I've changed a few files to make goji compilable and usable on windows by basically stubbing out parts that are einhorn/systemd-related - as I'd really like to use the original repository! I'm developing on windows (where it is a problem) and deploy to heroku (where it isn't) - my first stab was to fork, but with a fork I had to change the package paths which is not ideal.

P.S. Sorry for dummy commits - my git-fu is still weak - I had to erase changes I made to package paths.
Thanks in advance!
Dmitri.