Added optional argument.
Added optional argument.

squallyan/limejs,digitalfruit/limejs,wikieswan/limejs,Inframatic/theBasics,digitalfruit/limejs,srbala/limejs,Diaosir/limejs,GeorgeMe/limejs,ZzCalvinzZ/ludumdare26,GeorgeMe/limejs,runawaygo/Saver2012,Inframatic/theBasics,saulpw/nucleotron,runawaygo/Saver2012,saulpw/nucleotron,wikieswan/limejs,squallyan/limejs,oleg-kipling/limejs,Diaosir/limejs,wikieswan/limejs,srbala/limejs,sjamog/Lime-Projects,ZzCalvinzZ/ludumdare26,srbala/limejs,GeorgeMe/limejs,digitalfruit/limejs,oleg-kipling/limejs,squallyan/limejs,sjamog/Lime-Projects,Diaosir/limejs,sjamog/Lime-Projects,oleg-kipling/limejs