added whole system from ola4doc

sys/node_modules/es5-ext/math/log2/shim.js

@@ -0,0 +1,14 @@
+'use strict';
+
+var log = Math.log, LOG2E = Math.LOG2E;
+
+module.exports = function (x) {
+	if (isNaN(x)) return NaN;
+	x = Number(x);
+	if (x < 0) return NaN;
+	if (x === 0) return -Infinity;
+	if (x === 1) return 0;
+	if (x === Infinity) return Infinity;
+
+	return log(x) * LOG2E;
+};