There aren't too many interaction points:
The Sprite.texture attribute knows how to use pyglet texture objects. Also, if pyglet has been imported the rabbyt will automatically use pyglet for image loading if you provide a string for a texture.
Rabbyt's animations use whatever time you give it with rabbyt.set_time/rabbyt.add_time, so do something like "pyglet.clock.schedule(rabbyt.add_time)" to hook it up with pyglet's default clock.
If you're using pyglet you can just ignore rabbyt's Scheduler class. None of the rest of the library depends on it. (It probably should have been included in the library.)
Hope that helps :-)
MWM