Review

Added sketch unit tests. Note: they will sometimes fail unexpectedly. Please read the comment at the beginning of the 'creating a sketch' section.
Using transition methods (move, reflect, setOpacity, setColor) for sketches has been changed dramatically. These methods no longer need to specify a delay. Instead, call Sketch.initTrans() before a set of transition methods you want to occur one after another.
Also fixed small bug in radiogroup-spec.