OS hacking: Adding support for Ctrl+L and arrow keys in bash

In this video I add support for clearing the terminal by pressing Ctrl+L in bash. I also make it possible to use the arrow keys to browse the command history in bash. Recorded on 2019-01-30. Serenity is a 32-bit Unix-like operating system I'm implementing from scratch, just for fun. https://github.com/awesomekling/serenity