Updating usage function to armor against empty argument and to output to stderr.
Using _B style binary variables.
Configuring for git_history.sh functionality.
Whitespace consistency.
Adding git_history.sh
Using GIT_HISTORY_SCRIPT (as configured).

Not sure about the `git show -s -format="foo"` before the `git -log ...` but git log seems to be working okay, so the git_history.sh uses it exclusively.

git -show seemingly only got the latest log entry...?