fix popIndex calculation in CallEvent ctor
fix popIndex calculation in CallEvent ctor

joshuawarner32/avian,lostdj/avian,bigfatbrowncat/avian-pack.avian,marcinolawski/avian,joshuawarner32/avian,dicej/avian,bgould/avian,lostdj/avian,ucdseniordesign/avian,ucdseniordesign/avian,MaartenR/avian,getlantern/avian,bgould/avian,badlogic/avian,bigfatbrowncat/avian-pack.avian,lwahlmeier/avian,dicej/avian,getlantern/avian,dicej/avian,joshuawarner32/avian,MaartenR/avian,marcinolawski/avian,bigfatbrowncat/avian-pack.avian,getlantern/avian,marcinolawski/avian,MaartenR/avian,bigfatbrowncat/avian-pack.avian,lwahlmeier/avian,MaartenR/avian,badlogic/avian,lwahlmeier/avian,minor-jason/avian,bgould/avian,getlantern/avian,lostdj/avian,minor-jason/avian,minor-jason/avian,ucdseniordesign/avian,joshuawarner32/avian,marcinolawski/avian,lwahlmeier/avian,bgould/avian,badlogic/avian,badlogic/avian,minor-jason/avian,dicej/avian,ucdseniordesign/avian,lostdj/avian