Updated skin box hiding logic

Updated skin box hiding logic after testing a newer version PCK-Studio revealing the original logic wasn't accurate, also removed code that added arm and tool offsets to held items as it was not working correctly.

Minecraft.Client/ModelPart.cpp

@@ -13,7 +13,7 @@ void ModelPart::_init()
 	compiled=false;
 	bMirror = false;
 	visible = true;
-	hideWithHelmet = false;
+	hideWithArmor = 0L;
 	isArmorPart1 = false;
 	neverRender = false;
 	x=y=z = 0.0f;