Grants or denies access to a list of IP addresses
Yes. But why bother if you just want to block those annoying visitors? You'd better save bandwidth.
You can use the wildcard character "*". It is planned to add a mode that use regular expressions, but without any ETA.
Most probably because nobody submitted a translation for your language yet. But you can help. Read our guide for plugins translators at http://www.gabsoftware.com/tips/a-guide-for-wordpress-plugins-translators-gettext-poedit-locale/