ImageViewHandler: Fix Zoom and scroll on osx.
ImageViewHandler: Fix Zoom and scroll on osx.

wxdzju/Pangolin,mp3guy/Pangolin,tschmidt23/Pangolin,renzodenardi/Pangolin,tschmidt23/Pangolin,stevenlovegrove/Pangolin,pinglin/Pangolin,mp3guy/Pangolin,visigoth/Pangolin,arpg/Pangolin,mp3guy/Pangolin,pinglin/Pangolin,stevenlovegrove/Pangolin,renzodenardi/Pangolin,randi120/Pangolin,visigoth/Pangolin,arpg/Pangolin,tschmidt23/Pangolin,randi120/Pangolin,wxdzju/Pangolin,stevenlovegrove/Pangolin