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/common.inc

@@ -1,3 +1,15 @@
 <?php
-// Common setup for tests:
-?>
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+use AWS\CRT\CRT as CRT;
+
+abstract class CrtTestCase extends PHPUnit_Framework_TestCase {
+    // Ensure that after every test there are no errors in the CRT itself
+    protected function assertPostConditions() {
+        if (CRT::last_error()) {
+            $this->fail("Test left an error on the stack: " . CRT::error_name(CRT::last_error()));
+        }
+    }
+}