TODO in zpng-0.2.1 vs TODO in zpng-0.2.2

- old
+ new
@@ -1,16 +1,21 @@
+[ ] benchmark accessing very last PNG scanline
+[ ] use iostruct
+
 ways to hide info in PNG:
  * IHDR: longer than 13 bytes
  * IEND:
     * longer than  0 bytes
     * data after IEND
  * TEXT chunks
  * zTXT chunks
     * comp_method
+    * data after compressed data?
  * IDAT:
     * data after last scanline
     * last bits in scanline when bpp%8 != 0
  * PLTE:
     * raw letters
     * stegano
+    * many palette entries with same color => visually same pixels but, different color idx
  * custom chunks
  * crc