Fixed tags to only split/lowercase if a string
Fixed tags to only split/lowercase if a string

On the dev server, the mentoring search filter gets called twice. This only splits the text if it's a string.
heiglandreas/webapp,rocketpastsix/webapp,ericnkatz/phpmentoring,ericnkatz/phpmentoring,ericnkatz/phpmentoring,tdutrion/webapp,tdutrion/webapp,tristanbailey/webapp,heiglandreas/webapp,tdutrion/webapp,rocketpastsix/webapp,rocketpastsix/webapp,phpmentoring/webapp,heiglandreas/webapp,phpmentoring/webapp,phpmentoring/webapp,ericnkatz/phpmentoring,rocketpastsix/webapp,tdutrion/webapp,tristanbailey/webapp,tristanbailey/webapp,phpmentoring/webapp,tristanbailey/webapp,heiglandreas/webapp