Added local-repository option.

New ```local-repository``` option allows specification of a pre-existing local clone/checkout of a repository via ```repository-location```. This local repo checkout is copied into the qiime-deploy temp dir and used as if it was checked out from a remote repository.

This was tested on an Ubuntu EC2 instance with both SVN and git repos. Fixes #24.

A corresponding pull request to qiime-deploy-conf will also be issued and should be merged if/when this pull request is merged.