Added test-ffi target, use it in CI (#9)

* Added test-ffi target, use it in CI

* Added clang-format config, fixed RETURN_STRING API mismatch

* Skip installing php and packages on the PHP docker images

* Removed al2 job that was never going to work, and compiler tests

* Fixed basic test for extension loading

* Cleaned up lib structure, fixed tests

* use test-ci target to conditionally test in GitHub

* Use v0.8.1 of builder

tests/awscrt_000.phpt

@@ -1,4 +1,4 @@
---TEST--                                 
+--TEST--
 Version: Simple function call
 --SKIPIF--
 <?php
@@ -10,6 +10,5 @@ require_once(dirname(__FILE__) . '/common.inc');
 
 echo awscrt_version();
 ?>
-===DONE===
 --EXPECT--
 1.0.0-dev