Figure out why animations flicker without a very small epsilon

The Bezier curve library (https://github.com/arian/cubic-bezier) says that 0.01 to 0.1 should be sufficient for a 250ms animation but I ended up needing to use 1e-9 to get rid of the flickering with the Apple easing functions. The library does switch from Newton–Raphson to binary search at some point so 1e-9 may be crossing that threshold.