GroupSet::getByName added, typo fixed
GroupSet::getByName added, typo fixed

http://www.concrete5.org/developers/bugs/5-6-0-2/group_set.php-class-name-typo/
MichaelMaar/concrete5,matt9mg/concrete5,TimDix/concrete5,avdevs/concrete5,MichaelMaar/concrete5,matt9mg/concrete5,matt9mg/concrete5,avdevs/concrete5,MichaelMaar/concrete5,TimDix/concrete5,avdevs/concrete5,TimDix/concrete5