Class rename, composer add, phpUnit tests add

Rename the class from ReadEnvFile to DotEnv.
Add everything to a composer json file so it can be published to
composer repository.
Add phpUnit tests for system

vendor/webmozart/assert/src/InvalidArgumentException.php

@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of the webmozart/assert package.
+ *
+ * (c) Bernhard Schussek <bschussek@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Webmozart\Assert;
+
+class InvalidArgumentException extends \InvalidArgumentException
+{
+}