Updates bundled libpng to v1.5.13, built with VC2008 - requires update-workspaces. Refs #864

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@13035 3db68df2-c116-0410-a063-a993310a9797
Deletes obsolete/unused dll

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@13036 3db68df2-c116-0410-a063-a993310a9797
Merge remote-tracking branch 'remotes/trunk'