[Issue 81] Python 3 version of Statsite Sink and Vagrant update

[hkp]

Synthesize wasn't working for master, v4.0.0 and v.3.0.1. I did a quick port of the Python 2 script since that was what the errors were about. I decided to add it to this repo, since I didn't know if statsite would take the Python3 script, but I know that synthesize is dependent on this. Added the related change to Vagrantfile, so it'll work from the current instructions.