This adds a new build step executed after StepStartVmPaused. This sets
the "ssh_address" state variable to the IP of the host the VM was started on.
This enables SSH commands to work correctly in a pool environment.
This also modifies SSH calls to use this address rather than config.HostIp
Fixes#47
Compiles -- but xva create_instance is incomplete
Several changes were rolled into this commit, including:
- "export_format" is now "format", and "keep_instance" is "keep_vm"
- gox is used for building (with the intention of allowing
cross-compilation in the future)
