chore: drop pixels-rs and add egui w/ wgpu backend

src/bus.rs

@@ -73,7 +73,10 @@ impl Bus {
     fn tick(&mut self, limit: u8) {
         for _ in 0..limit {
             self.timer.tick();
-            self.cart.as_mut().map(|cart| cart.tick());
+
+            if let Some(c) = self.cart.as_mut() {
+                c.tick()
+            }
             self.ppu.tick();
             self.apu.tick(self.timer.divider);
             self.dma_tick()