Stop using nested viewports

src/main.rs

@@ -1,13 +1,13 @@
 use std::{path::PathBuf, process};
 
 use anyhow::Result;
-use application::Application;
+use app::Application;
 use clap::Parser;
 use emulator::EmulatorBuilder;
 use thread_priority::{ThreadBuilder, ThreadPriority};
 use winit::event_loop::{ControlFlow, EventLoop};
 
-mod application;
+mod app;
 mod audio;
 mod controller;
 mod emulator;