calcAbsDiffBetweenAngles() now handles angles that are unknown (NaN). calcSlidingStepLengthToOrigin() no longer returns Q since the calling function doesn't need it. Redesigned calculateIntervalStepLength() to ensure the step size is no smaller than it needs to be; currently isolates step length using secant method, or bisection if secant suggests a step length outside the range [0,1] (which it often does). TODO: Replace secant method with Newton iteration using numerical gradient (as suggested by Sherm).