Imported CRT FFI lib (#7)

* Added php7 library skeleton

* Re-worked Makefile.frag to use paths correctly

* Added gitignore for lib

* clang-format

* Remove symlinked api.h

* Copy api.h into lib/ as part of build

lib/crt.php

@@ -0,0 +1,35 @@
+<?php
+require_once('preload.php');
+
+final class CRT {
+    private static $ffi = null;
+    function __construct() {
+        if (is_null(self::$ffi)) {
+            try {
+                self::$ffi = FFI::cdef(file_get_contents(__DIR__ . "/api.h"), __DIR__ . "/libaws-crt-ffi.so");
+            } catch (Exception $e) {
+                echo 'Exception: ', $e->getMessage(), "\n";
+            }
+        }
+    }
+
+    function init() {
+        return self::$ffi->aws_crt_init();
+    }
+
+    function clean_up() {
+        return self::$ffi->aws_crt_clean_up();
+    }
+
+    function last_error() {
+        return self::$ffi->aws_crt_last_error();
+    }
+
+    function error_str($error) {
+        return self::$ffi->aws_crt_error_str((int) $error);
+    }
+
+    function error_name($error) {
+        return self::$ffi->aws_crt_error_name((int) $error);
+    }
+}