Set VM display name using hostname.

Sets the virtual machine's "display" name so it is more easily recognizable when viewing your list of VMs in the VirtualBox Manager (or VMware Fusion Library). This is especially handy if you work on many client projects and have a dozen different nearly-identical VMs in the list.

![puphpet-set-vm-displayname](https://cloud.githubusercontent.com/assets/637270/3290306/c766f1d4-f576-11e3-8da8-502064e76acd.PNG)