remove prototype pathops code

experimental/Intersection/IntersectionUtilities.h

-/*
- * Copyright 2012 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-// inline utilities
-/* Returns 0 if negative, 1 if zero, 2 if positive
-*/
-inline int side(double x) {
-    return (x > 0) + (x >= 0);
-}
-
-/* Returns 1 if negative, 2 if zero, 4 if positive
-*/
-inline int sideBit(double x) {
-    return 1 << side(x);
-}
-
-/* Given the set [0, 1, 2, 3], and two of the four members, compute an XOR mask
-   that computes the other two. Note that:
-
-   one ^ two == 3 for (0, 3), (1, 2)
-   one ^ two <  3 for (0, 1), (0, 2), (1, 3), (2, 3)
-   3 - (one ^ two) is either 0, 1, or 2
-   1 >> 3 - (one ^ two) is either 0 or 1
-thus:
-   returned == 2 for (0, 3), (1, 2)
-   returned == 3 for (0, 1), (0, 2), (1, 3), (2, 3)
-given that:
-   (0, 3) ^ 2 -> (2, 1)  (1, 2) ^ 2 -> (3, 0)
-   (0, 1) ^ 3 -> (3, 2)  (0, 2) ^ 3 -> (3, 1)  (1, 3) ^ 3 -> (2, 0)  (2, 3) ^ 3 -> (1, 0)
-*/
-inline int other_two(int one, int two) {
-    return 1 >> 3 - (one ^ two) ^ 3;
-}
-
-/* Returns -1 if negative, 0 if zero, 1 if positive
-*/
-inline int sign(double x) {
-    return (x > 0) - (x < 0);
-}
-
-inline double interp(double A, double B, double t) {
-    return A + (B - A) * t;
-}