Add production dependencies

node_modules/es5-ext/safe-to-string.js

@@ -0,0 +1,12 @@
+"use strict";
+
+var isCallable = require("./object/is-callable");
+
+module.exports = function (value) {
+	try {
+		if (value && isCallable(value.toString)) return value.toString();
+		return String(value);
+	} catch (e) {
+		return "<Non-coercible to string value>";
+	}
+};