[libpng16] Describe new simplified API in the manual pages

and cleaned up some indentation problems.
diff --git a/CHANGES b/CHANGES
index a4988a2..d278488 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3855,7 +3855,8 @@
   Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
     and unsigned long are of different sizes.
 
-Version 1.6.0beta05 [December 30, 2011]
+Version 1.6.0beta05 [January 11, 2012]
+  Updated manual with description of the simplified API (copied from png.h)
 
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