Update hot-phpunit-runner

[mikedfunk]

set a relative path to the composer autoload file so this can be installed globally too.

[slavahatnuke]

@mikedfunk thanks, for PR. could you implement and retest this:

foreach (array(__DIR__ . '/../../autoload.php', __DIR__ . '/../vendor/autoload.php', __DIR__ . '/vendor/autoload.php', __DIR__ . '/../../../autoload.php') as $file) {
    if (file_exists($file)) {
        require_once $file;
        break;
    }
}