Update GeoJSON definition with generics

geojson/geojson-tests.ts

@@ -54,7 +54,7 @@ var featureCollection: GeoJSON.FeatureCollection =  {
     }
 }
 
-var feature: GeoJSON.Feature = { 
+var feature: GeoJSON.Feature<GeoJSON.Polygon> = {
     type: "Feature",
     bbox: [-180.0, -90.0, 180.0, 90.0],
     geometry: {

geojson/geojson.d.ts

@@ -90,9 +90,9 @@ declare namespace GeoJSON {
     /***
     * http://geojson.org/geojson-spec.html#feature-objects
     */
-    export interface Feature extends GeoJsonObject
+    export interface Feature<T extends GeometryObject> extends GeoJsonObject
     {
-        geometry: GeometryObject;
+        geometry: T;
         properties: any;
         id?: string;
     }
@@ -100,9 +100,9 @@ declare namespace GeoJSON {
     /***
     * http://geojson.org/geojson-spec.html#feature-collection-objects
     */
-    export interface FeatureCollection extends GeoJsonObject
+    export interface FeatureCollection<T extends GeometryObject> extends GeoJsonObject
     {
-        features: Feature[];
+        features: Feature<T>[];
     }
 
     /***