fuse the Serial console to get the IP address and to see if the VM is up
and running
Add support for local socket to talk to the b2d VM's ttyS

This will provide us with a backchannel to get the host only IP on
VM platforms that don't have nat-style port forwarding, and hopefully
will make it possible to get a more reliable VM status
Merge pull request #140 from SvenDowideit/serial-console

Serial console