1. Open the app. The name of the app is defined in qDocName.
                        The client sends:
                        {
  "jsonrpc": "2.0",
  "id": 0,
  "method": "OpenDoc",
  "handle": -1,
  "params": [
    "ctrl00_migration_0.95_Small.qvf",
    "UserDirectory=QTSEL; UserId=smu"
  ]
}
                        The engine returns:
                        {
  "jsonrpc": "2.0",
  "id": 0,
  "result": {
    "qReturn": {
      "qType": "Doc",
      "qHandle": 1
    }
  },
  "change": [
    1
  ]
}
                        The app is opened and has 1 as a handle.
                        2. Check that the app is not empty.
                        The client sends:
                        {
  "jsonrpc": "2.0",
  "id": 2,
  "method": "GetAllInfos",
  "handle": 1,
  "params": []
}
                        The engine returns:
                        {
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "qInfos": [
      {
        "qId": "vEYgftD",
        "qType": "sheet"
      },
      {
        "qId": "mpHTWaD",
        "qType": "combochart"
      }
    ]
  }
}
                        The identifier (qId) and the type (qType) of the objects in the app are returned.
                        GetAllInfos method.