Use 'action' for VarientPicker sendAction

To call controller or router actions from within a component, you link the actions in the templates, and then call `this.sendAction('actionName')`

Something like this:

```javascript
App.SomeController = Ember.Controller.extend({
  actions: {
    doSomething: function(variant) {
      console.log('doSomething');
    },
    updateSomething: function(variant) {
      console.log('updateSomething');
    }
  }
});
```

```handlebars
{{view EmberStore.VariantPicker click="doSomething" change="updateSomething"}}
```

```coffeescript
EmberStore.VariantPicker = Ember.TextField.extend
  didInsertElement: ->
    view = this
    $('#' + this.elementId).select2
      width: '500px'
      ajax:
        url: '/api/variants'
        datatype: "json"
        data: (term, page) ->
          q:
            name_cont: term
        results: (data, page) ->
          results: data["variants"]
      formatResult: (variant) ->
        variant.name
      formatSelection: (variant) ->
        view.set('variant', variant)
        variant.name

  click: (e) ->
    this.sendAction('click', this.get('variant'))

  change: (e) ->
    this.sendAction('change', this.get('variant'))
```