Provide a better message for file modes

[bschwind]

Using innernet, you can run into messages like this:

[!] /etc/innernet is world-accessible (mode is 0o755). This is probably not what you want.
[*] fetching state for <interface> from server...
[!] /var/lib/innernet is world-accessible (mode is 0o755). This is probably not what you want.

This message should give a suggestion on what to do instead of just stating "probably not what you want".

Also, is it even a problem if the directory is "world-accessible"? This means someone can list the file name, but can't see the actual content in the files.