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

composer.json

@@ -27,13 +27,8 @@
             "src/"
         ]
     },
-    "autoload-dev": {
-        "classmap": [
-            "src/tests/"
-        ]
-    },
     "scripts": {
-        "test": "@php -d extension=modules/awscrt.so vendor/bin/phpunit src/tests"
+        "test": "@php -d extension=modules/awscrt.so vendor/bin/phpunit tests"
     },
     "license": "Apache-2.0"
 }