prep for 2023. Fixed many bugs. Added pdf guide

vendor/markbaker/complex/examples/testOperations.php

@@ -0,0 +1,34 @@
+<?php
+
+use Complex\Complex as Complex;
+
+include('../classes/Bootstrap.php');
+
+$values = [
+    new Complex(123),
+    new Complex(456, 123),
+    new Complex(0.0, 456),
+];
+
+foreach ($values as $value) {
+    echo $value, PHP_EOL;
+}
+
+echo 'Addition', PHP_EOL;
+
+$result = \Complex\add(...$values);
+echo '=> ', $result, PHP_EOL;
+
+echo PHP_EOL;
+
+echo 'Subtraction', PHP_EOL;
+
+$result = \Complex\subtract(...$values);
+echo '=> ', $result, PHP_EOL;
+
+echo PHP_EOL;
+
+echo 'Multiplication', PHP_EOL;
+
+$result = \Complex\multiply(...$values);
+echo '=> ', $result, PHP_EOL;