Update tooltip on date changed

Bound long date to computed property (addresses #15 )

src/app/src/components/common/DateFromNow.vue

@@ -20,13 +20,16 @@ export default {
     }
   },
   data () {
-    const dt = moment(this.value)
     return {
-      fromNow: dt.fromNow(),
-      actual: dt.format('LLLL'),
+      fromNow: moment(this.value).fromNow(),
       intervalId: null
     }
   },
+  computed: {
+    actual () {
+      return moment(this.value).format('LLLL')
+    }
+  },
   mounted () {
     this.intervalId = setInterval(this.updateFromNow, this.interval)
     this.$watch('value', this.updateFromNow)