Make sure the replay is stopped if the main menu is opened (fixes #95)

src/main/java/com/replaymod/replay/ReplayModReplay.java

@@ -195,6 +195,10 @@ public class ReplayModReplay {
         replayHandler = new ReplayHandler(replayFile, true);
     }
 
+    public void forcefullyStopReplay() {
+        replayHandler = null;
+    }
+
     public ReplayMod getCore() {
         return core;
     }

src/main/java/com/replaymod/replay/handler/GuiHandler.java

@@ -16,6 +16,8 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import static com.replaymod.replay.ReplayModReplay.LOGGER;
+
 public class GuiHandler {
     private static final int BUTTON_EXIT_SERVER = 1;
     private static final int BUTTON_ACHIEVEMENTS = 5;
@@ -102,6 +104,20 @@ public class GuiHandler {
             return;
         }
 
+        if (mod.getReplayHandler() != null) {
+            // Something went terribly wrong and we ended up in the main menu with the replay still active.
+            // To prevent players from joining live servers and using the CameraEntity, try to stop the replay now.
+            try {
+                mod.getReplayHandler().endReplay();
+            } catch (IOException e) {
+                LOGGER.error("Trying to stop broken replay: ", e);
+            } finally {
+                if (mod.getReplayHandler() != null) {
+                    mod.forcefullyStopReplay();
+                }
+            }
+        }
+
         @SuppressWarnings("unchecked")
         List<GuiButton> buttonList = event.buttonList;
         GuiButton button = new GuiButton(BUTTON_REPLAY_VIEWER, event.gui.width / 2 - 100,