Now works with boot2docker 1.3.0 on virtualbox (not tested with other pr...

Hi!

Now works with boot2docker 1.3.0 on virtualbox (not tested with other providers).

Should close #65 

I have the following in my vagrantfile wish the docker providers use:

```
 config.vm.provider "virtualbox" do |v|
    # On VirtualBox, we don't have guest additions or a functional vboxsf
    # in TinyCore Linux, so tell Vagrant that so it can be smarter.
#    v.check_guest_additions = false
#    v.functional_vboxsf     = false
    v.customize ["modifyvm", :id, "--memory", "4096"]
  end
```

Sincerely 
Mikael