Merge pull request #273 from rijn/253

IE<=11 do not support toString.

test/routers/notice.vue

@@ -0,0 +1,19 @@
+<template>
+    <i-button @click="pop">Pop</i-button>
+</template>
+<script>
+    export default {
+        methods: {
+            pop () {
+                for (let i = 0; i < 6; i++) {
+                    setTimeout(() => {
+                        this.$Notice.open({
+                            title: 'test',
+                            duration: 1.5 + i
+                        });
+                    }, i * 500);
+                }
+            }
+        }
+    }
+</script>