Add a doc to explain the limitations of garden windows
Add a doc to explain the limitations of garden windows

cloudfoundry/garden-windows,stefanschneider/garden-windows,cloudfoundry-incubator/garden-windows,cloudfoundry/garden-windows,cloudfoundry-incubator/garden-windows,stefanschneider/garden-windows,cloudfoundry-incubator/garden-windows,stefanschneider/garden-windows,cloudfoundry/garden-windows