Fix demo docker image to fetch latest 0.13.1 release and to use MGOS 3.1.2 (the latest version reference for brucepc/mapguide container)
Fix demo docker image to fetch latest 0.13.1 release and to use MGOS 3.1.2 (the latest version reference for brucepc/mapguide container)

Fixes #1126

jumpinjackie/mapguide-react-layout,jumpinjackie/mapguide-react-layout,jumpinjackie/mapguide-react-layout,jumpinjackie/mapguide-react-layout,jumpinjackie/mapguide-react-layout