openbabel png patch according http://www.mail-archive.com/openbabel-discuss@lists.sourceforge.net/msg02948.html and https://gist.github.com/fredrikw/5858168/raw
openbabel png patch according http://www.mail-archive.com/openbabel-discuss@lists.sourceforge.net/msg02948.html and https://gist.github.com/fredrikw/5858168/raw