Cleanup pass based on prior PRs (#21)

* Updates to stub generation

* More idiomatic fixes from PHP team

* Moved tests from src/tests -> tests, got rid of extension-only tests

* fixed up test paths, regenerated arginfo

tests/ErrorTest.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+use AWS\CRT\CRT;
+
+final class ErrorTest extends PHPUnit_Framework_TestCase {
+    private static $crt = null;
+    public static function setUpBeforeClass() {
+        self::$crt = new CRT();
+    }
+
+    public static function tearDownAfterClass() {
+        self::$crt = null;
+    }
+
+    public function testNoInitialError() {
+        $this->assertEquals(0, CRT::last_error());
+    }
+
+    public function testCanResolveErrorName() {
+        $this->assertEquals("AWS_ERROR_SUCCESS", CRT::error_name(0));
+    }
+
+    public function testCanResolveErrorStr() {
+        $this->assertEquals("Success.", CRT::error_str(0));
+    }
+}