Added png and z libs to plugin environment.
Added png and z libs to plugin environment.

ketchupok/csound,csound/csound,csound/csound,ketchupok/csound,csound/csound,ketchupok/csound,csound/csound,ketchupok/csound,ketchupok/csound,ketchupok/csound,csound/csound,csound/csound,csound/csound,ketchupok/csound,ketchupok/csound,ketchupok/csound,csound/csound,csound/csound,csound/csound,ketchupok/csound