fixes #607.

audit is now mostly rewritten for the new functionality. And
has new features like --check-permissions, --recursive and
--packages.

$ROOT/etc/apk/protected_files.d/*.list can now contain additional
protected paths, one path per line:

+etc
@etc/init.d
-tmp

+ will include the directory as protected configuration directory.
@ considers the directory protected, but will backup only symlinks.
- removes any protection

lbu should be modified to put include and exclude paths in
etc/apk/protected_files.d/lbu.list. Additionally, some packages
might provide their own listings.

E.g. ssh might want to provide ssh.list with something like:
+root/.ssh
+home/*/.ssh