[orx-triangulation] Improve triangulation, add kotlin/js support

orx-triangulation/src/commonMain/kotlin/Predicates.kt

@@ -0,0 +1,19 @@
+package org.openrndr.extra.triangulation
+
+internal fun orient2d(bx: Double, by: Double, ax: Double, ay: Double, cx: Double, cy: Double): Double {
+    // (ax,ay) (bx,by) are swapped such that the sign of the determinant is flipped. which is what Delaunator.kt expects.
+
+    /*
+    | a  b | = | ax - cx  ay - cy |
+    | c  d |   | bx - cx  by - cy |
+    */
+
+    val a = ax - cx
+    val b = ay - cy
+    val c = bx - cx
+    val d = by - cy
+
+    val determinant = ddDiffDd(twoProduct(a, d), twoProduct(b, c))
+
+    return determinant[1]
+}