More flexible bootstrap

bootstrap.php

<?php

$dirSep = DIRECTORY_SEPARATOR;
$boltRoot = realpath(__DIR__ . DIRECTORY_SEPARATOR . '..');

$autoloaderPaths = array(
  'Standard' => $boltRoot . $dirSep . 'vendor' . $dirSep . 'autoload.php',
  'Composer' => $boltRoot . $dirSep . '..' . $dirSep . '..' . $dirSep . 'autoload.php';
);

foreach ($autoloaderPaths as $name => $path) {
    if (file_exists($path)) {
        require_once $path;
        $configClass = 'Bolt\\Configuration\\' . $name;
        $config = new $configClass($boltRoot);
        break;
    }
}

if (!isset($config) || !$config instanceof \Bolt\Configuration\ResourceManager) {
    throw new Exception('Autoloader not found or configuration class instantiation failed.');
}

$config->verify();
$config->compat();