WIP 'docker share' using rsync or sshfs - only does 'pwd'

Thought I'd just try it :)

The `--share=smb` share driver flag does not work - we need to merge #245 and some docker/pkg/mflags changes (or #243 and and some more fixes)
These `tce-load` commands make me want to stab my eyes out, especially since I see the very existence of `tce-load` inside boot2docker as a bug, but I realize this is a first pass of "can this work?", so I won't beat this horse too roughly. :smile: