Provides simple mechanism for starting Animators when specific events occur.

This package provides classes for both using and subclassing that simplify the process of associating animations with events. Trigger and its subclasses associate specific events (subclasses of TriggerEvent) with listeners (as defined in Trigger subclasses). These listeners are then added (by the application) to appropriate objects. The animations are started when a Trigger detects that a specified event has occurred (through its listener).