Usage:
$ merged-branches.sh > DELETE-ME # Get all merged branches on the origin remote and put them into the DELETE-ME file
$ branch-owners.sh < DELETE-ME | sort > BRANCH-OWNERS # Map all the branches we just grabbed to the most recent author
$ delete-branches.sh < DELETE-ME # Actually delete all of the branches from origin
$ stale-branches.sh # Logs stale branches (those older than 6 months) to STALE and the rest to FRESH