attempt to fix weirdness in entry appdata

src/marathon/wad.rs

@@ -36,7 +36,7 @@ impl Wad<'_>
          if offset + size > b.len() {return err_msg("not enough data for entry");}
 
          let  chunks = get_chunks(&b[offset..offset+size], is_old)?;
-         let appdata = &b[p+entsize..p+entsize+appsize];
+         let appdata = &b[p..p+appsize];
 
          entries.insert(index, Entry{chunks, appdata});