Fixed a bug that save() ignores the 3rd argument "offset".
Fixed a bug that save() ignores the 3rd argument "offset".

chenkovsky/darts-clone,xen/darts-clone,pombredanne/darts-clone,hoganfan/darts-clone,hoganfan/darts-clone,demonshir/darts-clone,wells-xu/darts-clone,wells-xu/darts-clone,allenluce/darts-clone,allenluce/darts-clone,aminorex/darts-clone,xen/darts-clone,demonshir/darts-clone,pombredanne/darts-clone,aminorex/darts-clone,chenkovsky/darts-clone