Fix unintentional copyright infringement.

The original copy of the code in HttpHandler, HttpInitializer, etc, was used for various personal and in-house projects before being used here, and can be found at this URL:

https://github.com/SpigotMC/BungeeCord/tree/master/proxy/src/main/java/net/md_5/bungee/http

Said code is licensed under BungeeCord's license, which can be found here:

https://github.com/SpigotMC/BungeeCord/blob/master/LICENSE