initial commit - my (biased) osxc, dock + git

Abandoned most of the framework provided by osxc like xc-common, in
favor of my opinionated choices:
- doesn’t hardcode source folder to ~/src, provides var
- properly allows git config vars with defaults folder
- allows override of dockutil source clone if path is designated in
all.yml playbook
- breaks out ‘all’ machines vs. ‘Allister11’ host, sets git for all,
dock for Allister11