Defines target values at a specified point in time for a set of variables
that are interpolated along a Timeline.
The developer controls the interpolation of a set of variables for the
interval between successive key frames by providing a target value and an
Interpolator associated with each variable. The variables are
interpolated such that they will reach their target value at the specified
time. An onFinished function is invoked on each KeyFrame if one
is provided. A KeyFrame can optionally have a name, which
will result in a cuepoint that is automatically added to the Timeline.
Timeline, KeyValue, Interpolator