Added docker vagrant box & README 

This adds a VagrantFile to the cookbook-development repository which can be used to spin up a local VM capable of running docker. The README was added with instructions on how to use the VM, as well as information about the repository, how to use it in a cookbook, and what rake tasks it provides. 

The dependent vagrant box was built & uploaded to s3 using a combination of the [boot2docker](https://github.com/steeve/boot2docker) project and the [boot2docker-vagrant-box](https://github.com/mitchellh/boot2docker-vagrant-box) project. A new boot2docker ISO had to be generated which was listening on port 4243 & then the vagrant box was generated using the packer config in the boot2docker-vagrant-box repository. 

I'm aware there's another project called dvm that fnichol has made available but I choose not to use it for a few reasons:
- It requires installation via brew, making it less cross-platform & requiring additional steps
- It doesn't forward ports to the VM, rather it relies on you performing an `eval $(dvm env)` to get the current docker hostname. This doesn't play well with making the test-kitchen yml config deterministic.