improve and refactor geo json property handling

src/app/map/map.component.ts

@@ -53,7 +53,7 @@ export class MapComponent implements OnInit {
    * The properties of the current feature. The current layer is the layer beneath the cursor.
    */
   public currentFeatureInfo: any;
-  
+
   /**
    * A simple cache to save styles
    */
@@ -243,6 +243,10 @@ export class MapComponent implements OnInit {
     this.customLayerCollection.insertAt(event.currentIndex, tmp);
   }
 
+  /**
+   * Deletes a layer from custom layer collection
+   * @param layer
+   */
   deleteLayer(layer: VectorLayer) {
     this.customLayerCollection.remove(layer);
   }