Add logging (enabled with -v or --verbose).

This uses the hslogger framework underneath.
Add code to amend an existing repository.
Add signature for top-level binding.
Sort options alphabetically.

Also remove the short option for 'amend' in order to discourage
its usage.
Recreate directory after removing contents.

Otherwise things fall over when failing to find /var/log. It would be
nicer just to remove the contents, but this looks like it would be more
annoying. Should maybe think about recreating permissions.