update README.md with instructions for how to install from locally built gem until official gem gets published. update fog dependency to latest, 1.19. version bump.
update README.md with instructions for how to install from locally built gem until official gem gets published.
update fog dependency to latest, 1.19.
version bump.

mitchellh/vagrant-google,aaam/vagrant-google,Temikus/vagrant-google,mbrukman/vagrant-google,tcr/vagrant-google