Add support for layered deployment templates

[brandonmaul]

Hi. In an attempt to do a layered deployment as defined here I noticed that errors appeared when entering the desired properties in the format:

"exampleModule": {
      "properties.desired.property1": {
        "value": "exampleValue"
      }
    }

I believe this is due to the iot toolkit extension. Can it be updated to support these via a new deployment.template.json schema (Or by some other mechanism)?

Thanks