[devel] Bump to version libpng-1.5.2rc03

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.5.2rc02 - March 22, 2011
+Libpng 1.5.2rc03 - March 24, 2011
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,20 +9,20 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   1.5.2rc02.tar.xz (LZMA-compressed, recommended)
-   1.5.2rc02.tar.gz
-   1.5.2rc02.tar.bz2
+   1.5.2rc03.tar.xz (LZMA-compressed, recommended)
+   1.5.2rc03.tar.gz
+   1.5.2rc03.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp152r02.7z  (LZMA-compressed, recommended)
-   lp152r02.zip
+   lp152r03.7z  (LZMA-compressed, recommended)
+   lp152r03.zip
 
 Other information:
 
-   1.5.2rc02-README.txt
-   1.5.2rc02-LICENSE.txt
+   1.5.2rc03-README.txt
+   1.5.2rc03-LICENSE.txt
 
 Changes since the last public release (1.5.1):
 
@@ -64,6 +64,8 @@ Version 1.5.2rc02 [March 22, 2011]
   Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
     to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
 
+Version 1.5.2rc03 [March 24, 2011]
+
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