Expose port 4243 for VMWare Fusion and QEMU

Currently getting docker to expose itself on `0.0.0.0:4243` for the Mac OS X command line client is limited to VirtualBox detection (see https://github.com/steeve/boot2docker/pull/60). 

This PR adds support for both QEMU and VMWare Fusion. I've tested this in both the latest QEMU in brew and also VMWare Fusion 5 and VirtualBox 4.3.6.