Add more items, so that We can see the previous and next icons. (#635)

In high resolution screens, 15 items is just not enough to get the previous and next items to show on this example. So by adding more elements, we'll be able to see them.

src/examples/tabs/icons.vue

@@ -8,7 +8,7 @@
   >
     <v-tabs-slider color="yellow"></v-tabs-slider>
     <v-tab
-      v-for="i in 15"
+      v-for="i in 30"
       :href="'#tab-' + i"
       :key="i"
     >
@@ -17,7 +17,7 @@
 
     <v-tabs-items>
       <v-tab-item
-        v-for="i in 15"
+        v-for="i in 30"
         :id="'tab-' + i"
         :key="i"
       >