Updating the Grid System demo (showing how to use container/fluidcontainer). Fixed the layout of the Responsive Utilities demo too.
Merge remote-tracking branch 'origin/master'
Merge branch 'master' of https://github.com/gwtbootstrap3/gwtbootstrap3-demo

Conflicts:
	src/main/java/org/gwtbootstrap3/demo/client/application/css/GridSystemView.ui.xml