Sniff tweaks for extract and class names

Also merge the best of PEAR and WP classname Sniff and add our own flare as per: https://github.com/GigaOM/gigaom-plugins/pull/1722#issuecomment-39858984

do-while is now supported as requested here: https://github.com/GigaOM/gigaom-plugins/pull/1786#issuecomment-39858176

See: https://github.com/GigaOM/gigaom/issues/4226