Minimal GoJS Sample, reading JSON data

This is just like the Minimal sample, but this reads JSON data from the server.

Here are the contents of the `minimal.json` file:

    {
      "nodes":[
    { "key":"Alpha", "color":"lightblue" },
    { "key":"Beta", "color":"orange" },
    { "key":"Gamma", "color":"lightgreen" },
    { "key":"Delta", "color":"pink" }
      ],
      "links":[
    { "from":"Alpha", "to":"Beta" },
    { "from":"Alpha", "to":"Gamma" },
    { "from":"Beta", "to":"Beta" },
    { "from":"Gamma", "to":"Delta" },
    { "from":"Delta", "to":"Alpha" }
      ]
    }

Because this is a "minimal" sample, this sample has no way to update the data on the server.