Fix: Use a whitelist filter instead of blacklisting
Fix: Use a whitelist filter instead of blacklisting

PHPBenelux/opencfp,opencfp/opencfp,phphants/opencfp,OpenWestConference/opencfp,pmeth/opencfp,mdwheele/opencfp,MidwestPHP/opencfp_mwphp15,monoku/opencfp,DevOpsDaysChicago/opencfp,PHPBenelux/opencfp,opencfp/opencfp,OpenWestConference/opencfp,GrUSP/opencfp,jugisahunk/200OK_CFP,monoku/opencfp,mdwheele/opencfp,mdwheele/opencfp,DevOpsDaysChicago/opencfp,PHPBenelux/opencfp,GrUSP/opencfp,localheinz/opencfp,mdwheele/opencfp,OpenWestConference/opencfp,monoku/opencfp,phphants/opencfp,opencfp/opencfp,DallasPHP/opencfp,GrUSP/opencfp,localheinz/opencfp,MidwestPHP/opencfp_mwphp15,DevOpsDaysChicago/opencfp,DallasPHP/opencfp,pmeth/opencfp,monoku/opencfp,localheinz/opencfp,GrUSP/opencfp,MidwestPHP/opencfp_mwphp15,PHPBenelux/opencfp,phphants/opencfp,phphants/opencfp,jugisahunk/200OK_CFP,localheinz/opencfp,DallasPHP/opencfp,OpenWestConference/opencfp,jugisahunk/200OK_CFP,MidwestPHP/opencfp_mwphp15,pmeth/opencfp