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/nikic/php-parser/lib/PhpParser/ParserFactory.php

@@ -0,0 +1,44 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser;
+
+class ParserFactory
+{
+    const PREFER_PHP7 = 1;
+    const PREFER_PHP5 = 2;
+    const ONLY_PHP7 = 3;
+    const ONLY_PHP5 = 4;
+
+    /**
+     * Creates a Parser instance, according to the provided kind.
+     *
+     * @param int        $kind  One of ::PREFER_PHP7, ::PREFER_PHP5, ::ONLY_PHP7 or ::ONLY_PHP5
+     * @param Lexer|null $lexer Lexer to use. Defaults to emulative lexer when not specified
+     * @param array      $parserOptions Parser options. See ParserAbstract::__construct() argument
+     *
+     * @return Parser The parser instance
+     */
+    public function create(int $kind, Lexer $lexer = null, array $parserOptions = []) : Parser {
+        if (null === $lexer) {
+            $lexer = new Lexer\Emulative();
+        }
+        switch ($kind) {
+            case self::PREFER_PHP7:
+                return new Parser\Multiple([
+                    new Parser\Php7($lexer, $parserOptions), new Parser\Php5($lexer, $parserOptions)
+                ]);
+            case self::PREFER_PHP5:
+                return new Parser\Multiple([
+                    new Parser\Php5($lexer, $parserOptions), new Parser\Php7($lexer, $parserOptions)
+                ]);
+            case self::ONLY_PHP7:
+                return new Parser\Php7($lexer, $parserOptions);
+            case self::ONLY_PHP5:
+                return new Parser\Php5($lexer, $parserOptions);
+            default:
+                throw new \LogicException(
+                    'Kind must be one of ::PREFER_PHP7, ::PREFER_PHP5, ::ONLY_PHP7 or ::ONLY_PHP5'
+                );
+        }
+    }
+}