Fix rectangle annotations to conform to new GeoJS interface

OpenGeoscience/geojs#623 was resolved and #51
implicitly upgraded our version to incorporate the new interface. As a
result, trying to make a rectangle annotation threw a
"JSONRPCError (-32000): list index out of range".

js/src/MapObject.js

@@ -130,18 +130,9 @@ MapObject.prototype.add_annotation = function (annotation) {
  this.rpc_error.bind(this));
 };
 
-// Note: point/polygon's fire 'state' when they are added to
-// the map, while rectangle's fire 'add'
-// See: https://github.com/OpenGeoscience/geojs/issues/623
-MapObject.prototype.add_annotation_handler = function (evt) {
- var annotation = evt.annotation;
- if (annotation.type() === 'rectangle') {
- this.add_annotation(annotation);
- }
-};
 MapObject.prototype.state_annotation_handler = function (evt) {
  var annotation = evt.annotation;
- if (annotation.type() === 'point' || annotation.type() === 'polygon') {
+ if (_.contains(['point', 'polygon', 'rectangle'], annotation.type())) {
  this.add_annotation(annotation);
  }
 };
@@ -152,7 +143,6 @@ MapObject.prototype.add_annotation_layer = function (layer_name, params) {
  });
  layer.name(layer_name);
 
- layer.geoOn(geo_event.annotation.add, this.add_annotation_handler.bind(this));
 // layer.geoOn(geo_event.annotation.remove, handleAnnotationChange);
  layer.geoOn(geo_event.annotation.state, this.state_annotation_handler.bind(this));