Changes snap example to allow Circle creations

examples/snap.js

@@ -81,6 +81,8 @@ var Draw = {
     this.LineString.setActive(false);
     map.addInteraction(this.Polygon);
     this.Polygon.setActive(false);
+    map.addInteraction(this.Circle);
+    this.Circle.setActive(false);
   },
   Point: new ol.interaction.Draw({
     source: vector.getSource(),
@@ -94,6 +96,10 @@ var Draw = {
     source: vector.getSource(),
     type: /** @type {ol.geom.GeometryType} */ ('Polygon')
   }),
+  Circle: new ol.interaction.Draw({
+    source: vector.getSource(),
+    type: /** @type {ol.geom.GeometryType} */ ('Circle')
+  }),
   getActive: function() {
     return this.activeType ? this[this.activeType].getActive() : false;
   },