Introduced World Save Thread and some refractoring

src/main/java/kcauldron/KCauldronWorldSaveThread.java

@@ -0,0 +1,57 @@
+package kcauldron;
+
+import org.bukkit.craftbukkit.SpigotTimings;
+
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.MinecraftException;
+
+public class KCauldronWorldSaveThread extends Thread {
+    private final MinecraftServer mServer;
+    private int mLastSaveTick = -1;
+    private int mNextSaveTick = -1;
+
+    public KCauldronWorldSaveThread(MinecraftServer server) {
+        super(KCauldron.sKCauldronThreadGroup, "KCauldron World Save");
+        mServer = server;
+        setPriority(Thread.MIN_PRIORITY);
+        setDaemon(true);
+    }
+
+    @Override
+    public void run() {
+        KLog.get().info("Starting KCauldron World Saver thread...");
+        try {
+            while (!isInterrupted()) {
+                if (mLastSaveTick < 0) {
+                    mLastSaveTick = mServer.tickCounter;
+                }
+                mNextSaveTick = mLastSaveTick + mServer.autosavePeriod;
+                while (mNextSaveTick > mServer.tickCounter) {
+                    try {
+                        sleep((mNextSaveTick - mServer.tickCounter) * 50);
+                    } catch (InterruptedException e) {
+                        return;
+                    }
+                }
+                SpigotTimings.worldSaveTimer.startTiming();
+                try {
+                    mServer.serverConfigManager.saveAllPlayerData();
+                    mServer.saveAllWorlds(true);
+                } catch (MinecraftException e) {
+                    new RuntimeException("Error occurred during save world", e).printStackTrace();
+                }
+                SpigotTimings.worldSaveTimer.stopTiming();
+                mLastSaveTick = mServer.tickCounter;
+            }
+        } finally {
+            KLog.get().info("Stopping KCauldron World Saver thread...");
+        }
+    }
+
+    public void stopServer() {
+        interrupt();
+        while(isAlive()) {
+            Thread.yield();
+        }
+    }
+}