anchor.diff:      + Parameters
           + locatedAt: `-0.11,51.51` (string, required) - longitude,latitude;
           + fields: `airPollutionIndex,publishedAt` (string, required) - comma separated list of [airPollutionIndex,publishedAt] or single value;
  -        + timeZone: `Europe/Paris` (string, optional) - Time zone refers to the IANA Time Zone Database (TZDB).
  +        + timeZone: `Europe/London` (string, optional) - Time zone refers to the IANA Time Zone Database (TZDB).
   
   + Response 200 (application/json)
   
  
positive.code:               "forecasts": [
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-09T23:00:00Z",
                    "validUntil": "2017-05-10T23:00:00Z",
                    "pollenForecastRegion": "SE",
                    "pollenForecastRegionName": "London & South East England",
                    "pollenIndex": "Moderate",
                    "issuedAt": "2017-05-10T04:45:57Z"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-10T23:00:00Z",
                    "validUntil": "2017-05-11T23:00:00Z",
                    "pollenForecastRegion": "SE",
                    "pollenForecastRegionName": "London & South East England",
                    "pollenIndex": "Moderate",
                    "issuedAt": "2017-05-10T04:45:57Z"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-11T23:00:00Z",
                    "validUntil": "2017-05-12T23:00:00Z",
                    "pollenForecastRegion": "SE",
                    "pollenForecastRegionName": "London & South East England",
                    "pollenIndex": "Moderate",
                    "issuedAt": "2017-05-10T04:45:57Z"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-12T23:00:00Z",
                    "validUntil": "2017-05-13T23:00:00Z",
                    "pollenForecastRegion": "SE",
                    "pollenForecastRegionName": "London & South East England",
                    "pollenIndex": "Moderate",
                    "issuedAt": "2017-05-10T04:45:57Z"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-13T23:00:00Z",
                    "validUntil": "2017-05-14T23:00:00Z",
                    "pollenForecastRegion": "SE",
                    "pollenForecastRegionName": "London & South East England",
                    "pollenIndex": "Moderate",
                    "issuedAt": "2017-05-10T04:45:57Z"
                  }
                ]
              }
  
  
negative.code:               "forecasts": [
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-10T00:00:00+01:00",
                    "validUntil": "2017-05-11T00:00:00+01:00",
                    "forecastLocation": [ -0.1248, 51.5081 ],
                    "airPollutionIndex": 3,
                    "publishedAt": "2017-05-10T06:00:00+01:00"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-11T00:00:00+01:00",
                    "validUntil": "2017-05-12T00:00:00+01:00",
                    "forecastLocation": [ -0.1248, 51.5081 ],
                    "airPollutionIndex": 5,
                    "publishedAt": "2017-05-10T06:00:00+01:00"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-12T00:00:00+01:00",
                    "validUntil": "2017-05-13T00:00:00+01:00",
                    "forecastLocation": [ -0.1248, 51.5081 ],
                    "airPollutionIndex": 3,
                    "publishedAt": "2017-05-10T06:00:00+01:00"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-13T00:00:00+01:00",
                    "validUntil": "2017-05-14T00:00:00+01:00",
                    "forecastLocation": [ -0.1248, 51.5081 ],
                    "airPollutionIndex": 3,
                    "publishedAt": "2017-05-10T06:00:00+01:00"
                  },
                  {
                    "period": "PT24H",
                    "validFrom": "2017-05-14T00:00:00+01:00",
                    "validUntil": "2017-05-15T00:00:00+01:00",
                    "forecastLocation": [ -0.1248, 51.5081 ],
                    "airPollutionIndex": 3,
                    "publishedAt": "2017-05-10T06:00:00+01:00"
                  }
                ]
              }
  