Updated test bootstrapper to fall back to included autoloader

In the event that composer is not present, the test suite will fall
back to the provided autoloader. As part of this change the message for
when "composer install" hasn't been run has been made more predominate.

tests/bootstrap.php

@@ -17,8 +17,11 @@
 $filename = __DIR__ .'/../vendor/autoload.php';
 
 if (!file_exists($filename)) {
-    throw new Exception("You need to execute `composer install` before running the tests. (vendors are required for test execution)");
+    echo "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" . PHP_EOL;
+    echo "You need to execute `composer install` before running the tests." . PHP_EOL;
+    echo "(vendors are required for test execution)" . PHP_EOL;
+    echo "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" . PHP_EOL . PHP_EOL;
+    $filename = __DIR__ .'/../autoload.php';
 }
 
 require_once $filename;
-