Make easing function block return types explicit
Make easing function block return types explicit

This prevents issues where the return type is inferred to be a double or float, instead of CGFloat.

quyixia/AnimationEngine,msdgwzhy6/AnimationEngine,quyixia/AnimationEngine,intuit/AnimationEngine,DZNS/AnimationEngine,DZNS/AnimationEngine,msdgwzhy6/AnimationEngine,intuit/AnimationEngine,msdgwzhy6/AnimationEngine,DZNS/AnimationEngine,quyixia/AnimationEngine