Git-workflow

Added `workflow cleanup` command, which will tidy up commit templates in a repo.

Added `workflow finish` command, which will unset the commit template for a project branch and attempt to delete it.

Initial release with the following commands:

* `workflow start`: Create a new branch with the name format `[<client>-]<brief-description>-<yyyymmdd>-<initials>`. Optionally configures a commit template for the new branch.
* `workflow set-template`: Create and configure commit template for the current branch.
* `workflow unset-template`: Remove commmit template for a branch.