Remove functions wrapping Zeus

Project should be moving over to spring, as this is the 'blessed'
approach and is part of suspenders. Leaving these functions around adds
yet another layer of indirection to consider when trying to run these
commands:

* function wrapper
* binstub
* rbenv shim
* actual binary
Remove trailing whitespace in gitmessage
Automatically prune remote branches when fetching

* Removes the need to occasionally run `git remote prune`.
* Remove branches when fetching instead of deleting other branches.

https://trello.com/c/ePlghTll/249-configure-git-to-prune-on-fetch