Introduce sprout-osx-git & sprout-osx-git::authors

* To manage ~/.git-authors as expected by git-duet
* This cookbook can house all git related recipes
Merge pull request #67 from pivotal-sprout/add-git-authors

Introduce sprout-osx-git & sprout-osx-git::authors
Moved iTerm2 from PW to SOA
Adds shim for iTerm2 to PW
Updates iTerm2 syntax and idioms
Merge branch 'move_iterm2' into develop