Generated new code and added initial data handling

BlendFile/DNA/SpreadsheetInstanceID.cs

@@ -17,6 +17,9 @@ namespace BlendFile.DNA {
     public struct SpreadsheetInstanceID {
         [DNAFieldAttribute(0, "int", "reference_index", 4)]
         public int reference_index;
+        public SpreadsheetInstanceID() {
+            this.reference_index = default;
+        }
         public SpreadsheetInstanceID(int reference_index) {
             this.reference_index = reference_index;
         }