Fix parseShaped missing Empty slot item. Closes #3990

src/main/java/net/minecraftforge/common/crafting/CraftingHelper.java

@@ -308,6 +308,7 @@ public class CraftingHelper {
         }
 
         HashMap<Character, Ingredient> itemMap = Maps.newHashMap();
+        itemMap.put(' ', Ingredient.field_193370_a);
 
         for (; idx < recipe.length; idx += 2)
         {
@@ -315,6 +316,9 @@ public class CraftingHelper {
             Object in = recipe[idx + 1];
             Ingredient ing = CraftingHelper.getIngredient(in);
 
+            if (' ' == chr.charValue())
+                throw new JsonSyntaxException("Invalid key entry: ' ' is a reserved symbol.");
+
             if (ing != null)
             {
                 itemMap.put(chr, ing);