Output rework

Change the output of each command to simply output each git command in bold and the output of that command immediately after. 

Cleanup error messages to follow suit of what `git rebase` errors look like (but print in red to easily catch the eye).

To get a look, run a single cucumber test with the commands printed out.
 `cucumber features/git-ship.feature:3 DEBUG=true`
I'm against coloring the output red. The normal git commands don't show errors in red. I agree should not echo the output when it is empty