Update Vagrant Config [Ubuntu 12.04]

[jdu]

Reported on Ubuntu 12.04

The following error is sticky whenever you try to use the vagrant commands against the vagrantfile:

There were warnings and/or errors while loading your Vagrantfile.
Your Vagrantfile was written for an earlier version of Vagrant,
and while Vagrant does the best it can to remain backwards
compatible, there are some cases where things have changed
significantly enough to warrant a message. These messages are
shown below.

Warnings:
config.vm.customize calls are VirtualBox-specific. If you're
using any other provider, you'll have to find provider-specific configuration
to translate to manually in your Vagrantfile.```

Looks like the vagrant config isn't up to date with the latest version of Vagrant, it may be worth freezing at a specific Vagrant version as Vagrant provides a backlog of their versions.

[yarmoshuk]

vagrantfile updated to current version of vagrant, version info added to readme