Actually implement multiplayer

src/emulator.rs

@@ -114,6 +114,8 @@ impl Emulator {
             return Ok(());
         };
         self.load_rom(SimId::Player2, bytes)?;
+        let (first, second) = self.sims.split_at_mut(1);
+        first[0].link(&mut second[0]);
         Ok(())
     }