Including an external library functioning using namespace with xautoload

Question

I'm trying to include the PHPInsight library for performing sentiment analysis on user data.

Based on the demo file provided in it, I added it into the sites/all/libraries path so that it would read sites/all/libraries/phpInsight and tried to create an object

$sentiment = new \PHPInsight\Sentiment();

which resulted in blank screen.

Following this I looked into

1. Include a third party library using namespaces, dependencies and
2. https://www.drupal.org/node/1976234.

Apparently owing to a known constraint of D7 with namespace installed the xautoload and modified the hook_libraries_info as below

function analyzer_libraries_info() {
 $libraries['phpInsight'] = array(
  'name' => 'PHP Insight',
  'vendor url' => 'https://github.com/JWHennessey/phpInsight',
  'download url' => 'https://github.com/JWHennessey/phpInsight/archive/master.zip',
  'files' => array(
    'php' => array('autoload.php'),
    ),
  'xautoload' => function($adapter) {
    $adapter->namespaceRoot('\PHPInsight', 'lib');
  },
  );
 return $libraries;
}

I'm still uncertain about how to use the xautoload and my autoload file that needs to be included is in sites/all/libraries/phpInsight/autoload.php. Since I haven't used libraries API or PHP namespaces and some clarity on what needs to be done to get it included and instantiate the object with how it happens would be of great help.