making filter by topic take an optional array
making filter by topic take an optional array

TimDix/concrete5,TimDix/concrete5,MichaelMaar/concrete5,matt9mg/concrete5,avdevs/concrete5,MichaelMaar/concrete5,MichaelMaar/concrete5,matt9mg/concrete5,avdevs/concrete5,matt9mg/concrete5,avdevs/concrete5,TimDix/concrete5