Vagrant tuning

I added .vagrant to .gitignore, and changed the technology used to synchronize the project folder from the host to the guest.  I switched the box from 32 bit to 64 bit which should be fine on most machines that can run VirtualBox, and it better reflects the actual deployments.

I have been developing on the 64 bit box for several days without issue.

rsync-auto performs more quickly than virtualbox shared folders, and I hope it will support zeus, guard and autotest.  See https://www.vagrantup.com/blog/feature-preview-vagrant-1-5-rsync.html

Closes https://www.pivotaltracker.com/story/show/73659698  https://www.pivotaltracker.com/story/show/70826720
and 
https://www.pivotaltracker.com/story/show/70826980