Unit tests and I/O bindings (#8)

* Added composer config, added IO/error tests using phpunit

* Added ApiGen doc comments

* Added test to ensure last_error is not set from loading up the CRT

lib/lib.php

@@ -0,0 +1,7 @@
+<?php
+
+// Entry point to the CRT library. This file should be preloaded.
+
+// Import all of the library modules
+require_once('crt.php');
+require_once('io.php');