Add CSP sandbox

Fixes https://github.com/PrivateBin/PrivateBin/issues/168

Alos needed to run some Composer stuff, no idea why my diff was different.

vendor/composer/autoload_psr4.php

@@ -7,4 +7,5 @@ $baseDir = dirname($vendorDir);
 
 return array(
     'PrivateBin\\' => array($baseDir . '/lib'),
+    'CodeClimate\\PhpTestReporter\\' => array($vendorDir . '/codeclimate/php-test-reporter/src'),
 );