switch from dropdown to text input if > 10 shows; fix #28

This is for now hardcoded to 10, but in Aura 1.1 or 1.2 this
should become configurable by the dashboard user.

src/components/ShowSelector.vue

 <template>
   <b-row>
-    <b-col cols="3">
+    <b-col>
       <h3>{{ title }}</h3>
     </b-col>
-    <b-col align="right">
+    <b-col
+      v-if="shows.length > 10"
+      align="right"
+    >
       <b-input-group prepend="Select show:">
         <b-form-input
           v-model="inputSelector"
@@ -38,7 +41,7 @@
       </datalist>
     </b-col>
     <b-col
-      cols="3"
+      v-else
       align="right"
     >
       <b-dropdown