Minor fixes

1. Improve const correctness in a few places (such as `Container::getMaxStackSize()` -> `Container::getMaxStackSize() const`)

2. Use C++11 varargs for `I18n::get`, `Entity::newDoubleList` and `Language::getElement`

Minecraft.World/ChestTileEntity.h

@@ -59,7 +59,7 @@ public:
 	virtual void setCustomName(const wstring &name);
 	virtual void load(CompoundTag *base);
 	virtual void save(CompoundTag *base);
-	virtual int getMaxStackSize();
+	virtual int getMaxStackSize() const;
 	virtual bool stillValid(shared_ptr<Player> player);
 	virtual void setChanged();
 	virtual void clearCache();