Ralston2 implements Ralston's algorithm for solving ODEs by evaluating the rate at the initial state,
estimating the rate for the final state, and using a weighted average of these two rates to advance the state.
Steps (advances) the differential equations by the stepSize.
The ODESolver invokes the ODE's getState method to obtain the initial state of the system.
The ODESolver then uses this state estimate the rate a intermediate points.
Finally, the ODESolver advances the solution and copies the new state into the
state array at the end of the solution step.