Fix bug view{Will|did}{Appear|Disappear} is called twice
Fix bug view{Will|did}{Appear|Disappear} is called twice

orta/WYPopoverController,vitalys/WYPopoverController,Mindera/WYPopoverController,Medium/WYPopoverController,thelearningclinic/WYPopoverController,iv-mexx/WYPopoverController,jiamaozheng/WYPopoverController,Voxer/WYPopoverController,sammcewan/WYPopoverController,pinkowitz/WYPopoverController