Fixed NPE in player inventory + don't ignore the cancel state of world unloads

src/main/java/net/minecraft/server/InventoryPlayer.java

@@ -312,7 +312,7 @@ public class InventoryPlayer implements IInventory {
     }
 
     public boolean b(Block block) {
-        if (block.material.k()) {
+        if (block != null && block.material.k()) { // CraftBukkit - fix NPE
             return true;
         } else {
             ItemStack itemstack = this.getItem(this.itemInHandIndex);

src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -596,7 +596,7 @@ public final class CraftServer implements Server {
         }
 
         WorldUnloadEvent e = new WorldUnloadEvent(handle.getWorld());
-        pluginManager.callEvent(new WorldUnloadEvent(handle.getWorld()));
+        pluginManager.callEvent(e);
 
         if (e.isCancelled()) {
             return false;