Update to latest egui and glfw

[EriKWDev]

Made an initial attempt in #1 , but wasn't quite able to get all the way. A lot has changed but I think I'm close.

See the following implementations for up-to-date backends:

• miniquad: https://github.com/not-fl3/egui-miniquad/blob/master/src/painter.rs
• glium: https://github.com/emilk/egui/blob/master/crates/egui_glium/src/painter.rs
• glow: https://github.com/emilk/egui/blob/master/crates/egui_glow/src/painter.rs

[cohaereo]

Resolved in #1