Refactor UMD API

@matallo here it is man. 

Query UMD by ISO:
[http://localhost:8080/datasets/umd?begin=2000&end=2012&bust=1&iso=IDN](http://localhost:8080/datasets/umd?begin=2000&end=2012&bust=1&iso=IDN)

```json
{
   "iso":"IDN",
   "begin":"2000",
   "end":"2012",
   "dataset":"UMD",
   "gain_area":6970122.15434617,
   "loss_area":15785024.7103383,
   "units":"Ha"
}
```

Query UMD by GeoJSON:
[http://localhost:8080/datasets/umd?begin=2000&end=2012&bust=1&geom={%20%22type%22:%20%22Polygon%22,%20%22coordinates%22:%20[%20[%20[%20-65.390625,%20-2.108898659243126%20],%20[%20-65.390625,%20-14.264383087562637%20],%20[%20-50.2734375,%20-3.8642546157214084%20],%20[%20-59.4140625,%203.162455530237848%20],%20[%20-65.390625,%20-2.108898659243126%20]%20]%20]%20}](http://localhost:8080/datasets/umd?begin=2000&end=2012&bust=1&geom={%20%22type%22:%20%22Polygon%22,%20%22coordinates%22:%20[%20[%20[%20-65.390625,%20-2.108898659243126%20],%20[%20-65.390625,%20-14.264383087562637%20],%20[%20-50.2734375,%20-3.8642546157214084%20],%20[%20-59.4140625,%203.162455530237848%20],%20[%20-65.390625,%20-2.108898659243126%20]%20]%20]%20})

```json
{
   "loss_area":62223.678692568035,
   "begin":"2000",
   "units":"Ha",
   "end":"2012",
   "geom":{
      "type":"Polygon",
      "coordinates":[
         [
            [
               -65.390625,
               -2.108898659243126
            ],
            [
               -65.390625,
               -14.264383087562637
            ],
            [
               -50.2734375,
               -3.8642546157214084
            ],
            [
               -59.4140625,
               3.162455530237848
            ],
            [
               -65.390625,
               -2.108898659243126
            ]
         ]
      ]
   },
   "gain_area":4188.813495579543
}
```