#685 Add php implementation for PBKDF2

- Create php sample for PBKDF2
- Rename pbkdf2 java classes (remove Crypt prefix)
- Remove options from hash setting comment that should not be used

samples/website_integration/AuthMeController.php

@@ -109,7 +109,6 @@ abstract class AuthMeController {
      * @return string|null the hash, or null if unavailable (e.g. username doesn't exist)
      */
     private function getHashFromDatabase($username) {
-        // Add here your database host, username, password and database name
         $mysqli = $this->getAuthmeMySqli();
         if ($mysqli !== null) {
             $stmt = $mysqli->prepare('SELECT password FROM ' . self::AUTHME_TABLE . ' WHERE username = ?');