Make 'sendAction' available for extended textfields

Moving the 'sendAction' out of the closure would simply makes it available as a class method so that we can simply do

     App.ExtendedTextField = Ember.TextField.extend({
       focusOut: function(event){
         this.sendAction('focusOut',this,event);
       }

     /* Without reuse of sendAction ends up in DRY code where these things are already handled in 'sendAction'
    
       focusOut: function(event){
         var action = this.get('action');
         if(action) {       
           var controller = this.get('controller'),
                value = this.get('value'),
                bubbles = this.get('bubbles');            
          controller.send(action,value,this);        
          if(!bubbles){
            event.stopPropagation();   
          }
        }
      } 
      */
    });

cc @stefanpenner 

Related to #3054