State variables do not escape JSON keys correctly

[johnaohara]

Given a state;

RUN.output.1.test "some test"

The resulting JSON representation will be;

{ "RUN":
  { "output":
    { 1:
        { "test": "some test" }
    }
  }
}

Valid JSON should have keys escaped as strings, the key 1 should be escaped as a "1", i.e.

{ "RUN":
  { "output":
    { "1":
        { "test": "some test" }
    }
  }
}

Once Hyperfoil/yaup#33 is fixed, the version of yaup needs bumping