Reworked how Scratch Mark duration calculation happens: It now fires GetScratchMarkDurationEvent whenever a Survivor starts to run. However, this might not be accurate enough to represent immediate changes to the Scratch Mark duration, so the developer can now force this event to be called by using Survivor#resetScratchMarkDuration().
Fixed a bug regarding the Perk list
Changed the onCooldownOff() and onCooldownOn() methods' signature in order to support more CustomCooldowns.