Reduce Numerical.TOLERANCE to 1e-6, and use the same value across the boolean code.

Yields very good results now, across all tests.

src/path/Curve.js

@@ -1073,7 +1073,6 @@ new function() { // Scope for methods that require numerical integration
         // Let P be the first curve and Q be the second
         var q0x = v2[0], q0y = v2[1], q3x = v2[6], q3y = v2[7],
             tolerance = /*#=*/Numerical.TOLERANCE,
-            epsilon = 1e-10, // /*#=*/Numerical.EPSILON,
             // Calculate the fat-line L for Q is the baseline l and two
             // offsets which completely encloses the curve P.
             d1 = getSignedDistance(q0x, q0y, q3x, q3y, v2[2], v2[3]) || 0,
@@ -1089,7 +1088,7 @@ new function() { // Scope for methods that require numerical integration
             dp2 = getSignedDistance(q0x, q0y, q3x, q3y, v1[4], v1[5]),
             dp3 = getSignedDistance(q0x, q0y, q3x, q3y, v1[6], v1[7]),
             tMinNew, tMaxNew, tDiff;
-        if (q0x === q3x && uMax - uMin <= epsilon && recursion > 3) {
+        if (q0x === q3x && uMax - uMin <= tolerance && recursion > 3) {
             // The fatline of Q has converged to a point, the clipping is not
             // reliable. Return the value we have even though we will miss the
             // precision.

src/path/PathItem.Boolean.js

@@ -252,14 +252,7 @@ PathItem.inject(new function() {
      * with respect to a given set of monotone curves.
      */
     function getWinding(point, curves, horizontal, testContains) {
-        // We need to use a smaller tolerance here than in the rest of the
-        // library when dealing with curve time parameters and coordinates, in
-        // order to get really precise values for winding tests. 1e-7 was
-        // determined through a lot of trial and error, and boolean-test suites.
-        // Further decreasing it produces new errors.
-        // The value of 1e-7 also solves issue #559:
-        // https://github.com/paperjs/paper.js/issues/559
-        var tolerance = 1e-7,
+        var tolerance = /*#=*/Numerical.TOLERANCE,
             tMin = tolerance,
             tMax = 1 - tMin,
             x = point.x,

src/util/Numerical.js

@@ -63,7 +63,7 @@ var Numerical = new function() {
         cos = Math.cos,
         PI = Math.PI,
         isFinite = Number.isFinite,
-        TOLERANCE = 1e-5,
+        TOLERANCE = 1e-6,
         EPSILON = 1e-13,
         MACHINE_EPSILON = 1.12e-16;