BaseSpringSystem maintains the set of springs within an Application context. It is responsible for
Running the spring integration loop and maintains a registry of all the Springs it solves for.
In addition to listening to physics events on the individual Springs in the system, listeners
can be added to the BaseSpringSystem itself to provide pre and post integration setup.
SpringChain is a helper class for creating spring animations with multiple springs in a chain.
Chains of springs can be used to create cascading animations that maintain individual physics
state for each member of the chain. One spring in the chain is chosen to be the control spring.
Springs before and after the control spring in the chain are pulled along by their predecessor.
You can change which spring is the control spring at any point by calling
{@link SpringChain#setControlSpringIndex(int)}.
This is a wrapper for BaseSpringSystem that provides the convenience of automatically providing
the AndroidSpringLooper dependency in {@link SpringSystem#create}.
