WIP nipypification of pydeface

[Shotgunosine]

I've tried to overhaul pydeface so that the utility functions create and manipulate nipype workflows. TODO: deface_node and follower_node are writing directly to output directories and not writing to their working directories and then moving final outputs from the datasink to an appropriate location

[effigies]

This will need significant rewriting, so I'm going to close this. Please reopen if you do want to try again.