Updated common.php Implemented ban feature for Proxy & Cloud-IPs (apache only)

Ban feature for Apache servers updated so that IPs, even from a proxy client will successfully be banned via .htaccess.
Additionally implemented ban entry for Cloud/Cluster/Load-Balancer-Hosted WP-Installs, enabling them to ban IPs as well
Merge pull request #34 from kalvindukes/master

Overhauled implementation of ban feature (successfully bans Proxy-IPs + enables cloud-hosted WP-installs to use ban feature)