Version Control Agnosticism

[JohnMurray]

There are a few places in the codebase that reference git commands. This should be extracted out into a vcs module that can be extended to support any version control system.

Any version control actions should be turned off by default and enabled with the use_vcs config key, of which the value will contain the VCS to be used (e.g git, hg, svn, etc).