Merge internal fixes from the last few days

Between-Meals
* Switch to forking `git` for diffs - significant speed incrase
* Fix 'status' command not respecting vcs_path

Taste-Tester
* Error on invalid nodes
* Add hook-point for adding extra stuff to remote client.rb
* Switch to using a single client.rb file on the remote side
Merge pull request #22 from jaymzh/sync

Merge internal fixes from the last few days