[libpng17] Bump version to 1.7.0beta48

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.7.0beta47 - January 27, 2015
+Libpng 1.7.0beta48 - January 29, 2015
 
 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
 
-   1.7.0beta47.tar.xz (LZMA-compressed, recommended)
-   1.7.0beta47.tar.gz
+   1.7.0beta48.tar.xz (LZMA-compressed, recommended)
+   1.7.0beta48.tar.gz
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp170b47.7z  (LZMA-compressed, recommended)
-   lp170b47.zip
+   lp170b48.7z  (LZMA-compressed, recommended)
+   lp170b48.zip
 
 Other information:
 
-   1.7.0beta47-README.txt
-   1.7.0beta47-LICENSE.txt
-   libpng-1.7.0beta47-*.asc (armored detached GPG signatures)
+   1.7.0beta48-README.txt
+   1.7.0beta48-LICENSE.txt
+   libpng-1.7.0beta48-*.asc (armored detached GPG signatures)
 
 Changes since the last public release (1.6.0):
 
@@ -688,7 +688,7 @@ Version 1.7.0beta46 [January 2, 2015]
   Fixed byte order in 2-byte filler, in png_do_read_filler().
   Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
 
-Version 1.7.0beta47 [January 27, 2015]
+Version 1.7.0beta47 [January 29, 2015]
   Made the check for out-of-range values in png_set_tRNS() detect
     values that are exactly 2^bit_depth, and work on 16-bit platforms.
   Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
@@ -697,6 +697,8 @@ Version 1.7.0beta47 [January 27, 2015]
   Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
     pngset.c to avoid warnings about dead code.
 
+Version 1.7.0beta48 [January 29, 2015]
+
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