fixed handling of multidata png files

git-svn-id: http://ocamllibs.googlecode.com/svn/trunk@276 21970f9d-2756-cbab-44b1-85fcaa48d7c2
minor

git-svn-id: http://haxe.googlecode.com/svn/trunk@6385 f16182fa-f095-11de-8f43-4547254af6c6
fixed issue #1575

git-svn-id: http://haxe.googlecode.com/svn/trunk@6386 f16182fa-f095-11de-8f43-4547254af6c6
Merge branch 'haxe/master'
Merge branch 'ocamllibs/master'