Suggest testing with "Vagrant Gopher"

* A Vagrantfile at the root of the src folder means one box can be used for testing all Go projects instead of just fsnotify
* Updates to the Vagrantfile can happen in one place
* One less file to drop when fsnotify moves to the standard library #13.
Merge pull request #80 from gophertown/contrib

Suggest testing with "Vagrant Gopher"