Remove BulletPHP.

README.md

 ### Micro Frameworks
 *Micro frameworks and routers.*
 
-* [Bullet PHP](http://bulletphp.com/) - A micro framework for building REST APIs.
 * [Laravel-Zero](https://laravel-zero.com) - A micro-framework for console applications.
 * [Lumen](https://lumen.laravel.com) - A micro-framework by Laravel.
 * [Mezzio](https://getexpressive.org/) - A micro-framework by Laminas.