Programmatic way to draw a filter circle
function(filter) {
		// Set startLatLng so edits remember the starting point
		this._startLatLng = filter.center;

		// We don't need to add the circle since it's only added while editing. In this case, we just create a shape and return it
		var shape = new L.Circle(filter.center, filter.radius, this.options.shapeOptions);

		return { type: 'circle', layer: shape };
	}