Corrects the undefined (and mixed) encoding in the ChangeLog files

The inconsistent encoding of this file causes problems with
file handling in downstream projects. This patch corrects this
by converting it to a clean UTF8 type.

ChangeLog

@@ -4,7 +4,7 @@
 Changes in 1.2.8 (28 Apr 2013)
 - Update contrib/minizip/iowin32.c for Windows RT [Vollant]
 - Do not force Z_CONST for C++
-- Clean up contrib/vstudio [Ro§]
+- Clean up contrib/vstudio [Ro§]
 - Correct spelling error in zlib.h
 - Fix mixed line endings in contrib/vstudio
 
@@ -564,7 +564,7 @@ Changes in 1.2.3.1 (16 August 2006)
 - Update make_vms.com [Zinser]
 - Use -fPIC for shared build in configure [Teredesai, Nicholson]
 - Use only major version number for libz.so on IRIX and OSF1 [Reinholdtsen]
-- Use fdopen() (not _fdopen()) for Interix in zutil.h [BŠck]
+- Use fdopen() (not _fdopen()) for Interix in zutil.h [Bck]
 - Add some FAQ entries about the contrib directory
 - Update the MVS question in the FAQ
 - Avoid extraneous reads after EOF in gzio.c [Brown]
@@ -1178,7 +1178,7 @@ Changes in 1.0.6 (19 Jan 1998)
         386 asm code replacing longest_match().
    contrib/iostream/ by Kevin Ruland <kevin@rodin.wustl.edu>
         A C++ I/O streams interface to the zlib gz* functions
-   contrib/iostream2/  by Tyge Løvset <Tyge.Lovset@cmr.no>
+   contrib/iostream2/  by Tyge Løvset <Tyge.Lovset@cmr.no>
         Another C++ I/O streams interface
    contrib/untgz/  by "Pedro A. Aranda Guti\irrez" <paag@tid.es>
         A very simple tar.gz file extractor using zlib