"Fake" split-screen

An intermediary step between full in-game split-screen could be achieved by simply smartly detecting other minecraft windows and utilising borderless windows to achieve a split-screen look.

Normal borderless fullscreen simply tells the OS to remove window borders, and sets the size and position to fill the screen. This could be adapted to manage both windows and position them in a split-screen view.

Problems to overcome

• Currently, both instances will try to read the same config file, and have no way to communicate with
  eachother. This prevents changing any configs as it will behave funnily.

Issues with this implementation

• Not ideal for system performance. Loading resources twice in RAM is very bad and there are a lot of systems
  in the game that only need to run once.
• Running two instances of Minecraft will cause config issues with every mod, including vanilla options.txt

The issue names no repository files, tests, or entry points. Begin by locating the borderless-fullscreen/window-management code and how separate instances read config files, including options.txt; define done around two Minecraft windows positioned in a split-screen view without the described configuration conflicts.