Clear DataAccessorCommon instance when leaving world (#16)

src/main/java/mcp/mobius/waila/api/impl/DataAccessorCommon.java

@@ -212,5 +212,4 @@ public class DataAccessorCommon implements IWailaCommonAccessor, IWailaDataAcces
     public String getBlockQualifiedName() {
         return this.blockResource;
     }
-
 }

src/main/java/mcp/mobius/waila/client/ProxyClient.java

@@ -4,9 +4,12 @@ import net.minecraft.block.Block;
 import net.minecraft.entity.Entity;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.world.WorldEvent;
 
 import cpw.mods.fml.common.Loader;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
 import mcp.mobius.waila.Waila;
+import mcp.mobius.waila.api.impl.DataAccessorCommon;
 import mcp.mobius.waila.api.impl.ModuleRegistrar;
 import mcp.mobius.waila.cbcore.LangUtil;
 import mcp.mobius.waila.gui.truetyper.FontLoader;
@@ -61,6 +64,14 @@ public class ProxyClient extends ProxyServer {
         ModuleRegistrar.instance().registerTooltipRenderer("waila.health", new TTRenderHealth());
         ModuleRegistrar.instance().registerTooltipRenderer("waila.stack", new TTRenderStack());
         ModuleRegistrar.instance().registerTooltipRenderer("waila.progress", new TTRenderProgressBar());
+
+        MinecraftForge.EVENT_BUS.register(new Object() {
+
+            @SubscribeEvent
+            public void onWorldUnload(WorldEvent.Unload event) {
+                DataAccessorCommon.instance = new DataAccessorCommon();
+            }
+        });
     }
 
     @Override