Fix NPE in machine builtin model builder (#142)

Author: Swedz

src/main/java/net/swedz/tesseract/neoforge/compat/mi/machine/builder/HatchMachineBuilder.java

@@ -115,7 +115,10 @@ public HatchMachineBuilder builtinModel(MachineCasing casing, String overlayFold
 		{
 			// Hatches by default have a front and side overlay
 			b.front().side();
-			builder.accept(b);
+			if(builder != null)
+			{
+				builder.accept(b);
+			}
 		});
 	}
 

src/main/java/net/swedz/tesseract/neoforge/compat/mi/machine/builder/SingleBlockCraftingMachineBuilder.java

@@ -48,7 +48,10 @@ public SingleBlockCraftingMachineBuilder builtinModel(MachineCasing casing, Stri
 		{
 			// Single block crafting machines by default have a front and active overlay
 			b.front().active();
-			builder.accept(b);
+			if(builder != null)
+			{
+				builder.accept(b);
+			}
 		});
 	}
 

src/main/java/net/swedz/tesseract/neoforge/compat/mi/machine/builder/SpecialMachineBuilder.java

@@ -42,7 +42,10 @@ public SpecialMachineBuilder builtinModel(MachineCasing casing, String overlayFo
 		{
 			// Machines by default have a front and active overlay
 			b.front().active();
-			builder.accept(b);
+			if(builder != null)
+			{
+				builder.accept(b);
+			}
 		});
 	}