- main now handles exit with a function, not a goto.
- main creates a test layout. Will add buttons when the things is working, just to test direct event handling and such things.
- Started engine-wide events (input events) struct creation. Still have to change message passing to use event_t pointers, to allow polymorphic events.
- sys_gui draws active layout (TODO: think about how to manage multiple layouts at the same time).
- Shader loading, compilation and linking.
- Started simple gui::component::button.
- Create a shader program to test some rendering.