README: git-recent-branches requires GitPython, say so

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
archive-branch: list git-config hooks upfront

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
README: improve wording a bit

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>