This allows importing of external libraries into externals/ without
having to reformat them. Unfortunately it also allows whitespace to be
introduced in files like the root CMakeLists.txt, but that is a small
downside compared to the tradeoff.
Remove unneeded stuff from pre-commit script
The check against an empty commit was not needed (it is only a security for the 1st commit after git init).
It could also possibly pose problems because of the redirection to /dev/null on some windows systems.
newline at EOF & fixed indent