Update zlib to 1.2.8

git-svn-id: http://miranda.googlecode.com/svn/trunk@14438 83df23c2-51fd-11de-bb24-2d5e9b4af41d
Bump version

git-svn-id: http://miranda.googlecode.com/svn/trunk@14439 83df23c2-51fd-11de-bb24-2d5e9b4af41d