Reduce CURVETIME_EPSILON to 1e-8.

src/util/Numerical.js

@@ -142,7 +142,7 @@ var Numerical = new function() {
          * cannot be smaller, because errors add up to around 2e-7 in the bezier
          * fat-line clipping code as a result of recursive sub-division.
          */
-        CURVETIME_EPSILON: 4e-7, // NOTE: 2e-7 doesn't work in some edge-cases
+        CURVETIME_EPSILON: 1e-8,
         /**
          * The epsilon to be used when performing "geometric" checks, such as
          * distances between points and lines.