Switch to v-if to hide message.

This was causing extra space when the message was empty.

Author: BigBlueHat

playground/next/index.html

@@ -112,7 +112,7 @@ <h2 class="ui massive header">JSON-LD Playground</h2>
   <!-- main editor area -->
   <div class="ui one column wide compact grid container" :class="[editorColumns]">
     <div class="column" :class="{ 'sixteen wide':  editorColumns == '' }">
-      <div class="ui icon message" v-show="message.text" :class="message.type">
+      <div class="ui icon message" v-if="message.text" :class="message.type">
         <i class="icon" :class="{
           'info circle': message.type == 'info',
           'check circle': message.type == 'success',