fix issue with several events map-is-initialized

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vue-yandex-maps",
-  "version": "0.5.4",
+  "version": "0.5.5",
   "description": "Yandex Maps component for VueJS.",
   "main": "vue-yandex-maps.js",
   "jsnext:main": "./src/index.js",

src/Marker.js

@@ -1,3 +1,5 @@
+import * as utils from './utils';
+
 export default {
     props: {
         coords: {
@@ -26,7 +28,8 @@ export default {
     render() {
     },
     watch: {
-        coords() {
+        coords(newVal, oldVal) {
+            if (utils.objectComparison(newVal, oldVal)) { return; } 
             this.$ymapEventBus.initMap && this.$ymapEventBus.initMap();
         }
     }

src/YMap.js

@@ -1,5 +1,5 @@
 import Vue from 'vue';
-import * as utils from './utils'
+import * as utils from './utils';
 
 export default {
     data() {
@@ -52,7 +52,12 @@ export default {
                 return ['map', 'satellite', 'hybrid'].includes(val)
             }
         },
-        placemarks: Array
+        placemarks: {
+            type: Array,
+            default() {
+                return [];
+            }
+        }
     },
     computed: {
         coordinates() {
@@ -178,7 +183,8 @@ export default {
             this.myMap.geoObjects.add(myGeoObjects);
 
             utils.createClusters(markers, this.clusterOptions, this.myMap)
-                .then(() => this.$emit('map-was-initialized', this.myMap));
+
+            this.$emit('map-is-initialized', this.myMap)
         }
     },
     watch: {

src/utils.js

@@ -18,7 +18,6 @@ export function createClusters(markers, options, map) {
         clusterer.add(clusters[clusterName]);
         map.geoObjects.add(clusterer);
     }
-    return Promise.resolve();
 }
 
 export function getIconPreset(marker) {