In addition to the pre-existing normal and regular expression filters a
keyword mode is added. This filter matches if the referer string
contains a given keyword (case insensitive).
The settings page now features the 2 column layout like generated by WP
settings API. The regular expression selects are slightly rewritten in
preparation of additional mathing methods.
All PHP classes have been reworked to match the WP coding standard. This includes mostly code styling, but also the use of wp_ functions instead of PHP builtins.
