V3 - Remove mutable class properties plus other misc changes (#781)

* Remove the mutableValue prop in the Select component.

* Add back mutable value when Vue Select has to manage its own value.

* Remove mutableOptions, valueAsAarray. Update webpack minifer to use Terser.

* Fix tabbing

* Fix bug with showClearButton

* Fix tests.

* Call clearSelection when possible

* Update dev sandbox to have all three options for setting value.

* Update dev sandbox to display current value

* Remove unused karma test setup.

* Revert onInput name change.

* Use coveralls

* Change this.internalValue to this.$data._value.

* Remove onInput prop and replace with internal method, updateValue.

* Update tests.

* Rename optionObjectComparator to optionComparator.

dev/Dev.vue

@@ -2,7 +2,18 @@
   <div id="app">
     <sandbox hide-help>
       <template slot-scope="config">
+      
+      <p>Value managed by `v-model`:</p>
+      <v-select v-model="vModelValue" v-bind="config" />
+      <pre><code>`v-model` value: {{ vModelValueStringified }}</code></pre>
+      <hr />
 
+      <p>Value managed by `:value` and `@input`:</p>
+      <v-select :value="valueProp" @input="changeValueProp" v-bind="config" />
+      <pre><code>value passed to `@input`: {{ valuePropStringified }}</code></pre>
+      <hr />
+
+      <p>Value managed by Vue Select internally:</p>
       <v-select v-bind="config" />
 
       </template>
@@ -18,6 +29,30 @@ import Sandbox from '../docs/.vuepress/components/Sandbox';
 
 export default {
   components: {Sandbox, vSelect},
+  data: () => ({
+    vModelValue: {
+      value: 'CA',
+      label: 'Canada'
+    },
+    valueProp: {
+      value: 'US',
+      label: 'United States'
+    }
+  }),
+  methods: {
+    changeValueProp(value) {
+      this.valueProp = value;
+    }
+  },
+  computed: {
+    vModelValueStringified() {
+      return JSON.stringify(this.vModelValue, null, 2);
+    },
+
+    valuePropStringified() {
+      return JSON.stringify(this.valueProp, null, 2);
+    }
+  }
 };
 </script>
 
@@ -32,4 +67,12 @@ export default {
   #app {
     height: 100%;
   }
+
+  hr {
+    border: none;
+    border-bottom: 1px solid #cacaca;
+    margin-bottom: 1em;
+    padding-top: 1em;
+    width: 90%;
+  }
 </style>