Fix WorldClient memory leak (#9)

Co-authored-by: Maya <10861407+serenibyss@users.noreply.github.com>

src/main/scala/mrtjp/relocation/events.scala

@@ -52,7 +52,9 @@ object RelocationClientEventHandler {
 
   @SubscribeEvent
   def clientTick(event: TickEvent.ClientTickEvent) {
-    if (event.phase == TickEvent.Phase.END)
+    if (event.phase == TickEvent.Phase.END) {
       MovementManager2.onTick(true)
+      MovingRenderer.onTick()
+    }
   }
 }

src/main/scala/mrtjp/relocation/renders.scala

@@ -106,6 +106,13 @@ object MovingRenderer {
         render(b.x, b.y, b.z, renderPos(s, frame))
   }
 
+  def onTick() = {
+    if (oldWorld != null && world == null) {
+      oldWorld = null
+      renderBlocks = null
+    }
+  }
+
   def onPreRenderTick(time: Float) {
     isRendering = true
     frame = time