prep for 2023. Fixed many bugs. Added pdf guide

vendor/markbaker/matrix/examples/test.php

@@ -0,0 +1,19 @@
+<?php
+
+include __DIR__ . '/../classes/Bootstrap.php';
+
+$grid1 = [
+    [1, 3, 2],
+    [2, 3, 1],
+];
+
+$grid2 = [
+    [1, 6],
+    [0, 1],
+];
+
+$matrix = new Matrix\Matrix($grid1);
+
+$new = $matrix->directsum(new Matrix\Matrix($grid2));
+
+var_dump($new);