add some validation to row edit, better handle setting null cols with empty

porklib/Exceptions/SimpleValidationException.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace MightyPork\Exceptions;
+
+use Illuminate\Contracts\Support\MessageProvider;
+use Illuminate\Support\MessageBag;
+
+class SimpleValidationException extends RuntimeException implements MessageProvider
+{
+    /** @var MessageBag */
+    private $mb;
+
+    /**
+     * FBValidationException constructor.
+     *
+     * @param string|MessageProvider $key
+     * @param string $message
+     */
+    public function __construct($key, $message = null)
+    {
+        if (is_null($message)) {
+            $this->mb = $key->getMessageBag();
+        } else {
+            $mb = new MessageBag();
+            $mb->add($key, $message);
+            $this->mb = $mb;
+        }
+
+        $str = '';
+        foreach ($this->mb->getMessages() as $key => $errors) {
+            $str .= $key . ': ' . implode(', ', $errors) . "\n";
+        }
+
+        parent::__construct($str);
+    }
+
+    /**
+     * Get the messages for the instance.
+     *
+     * @return MessageBag
+     */
+    public function getMessageBag()
+    {
+        return $this->mb;
+    }
+}