对应Bootstrap progress组件，对Bootstrap progress组件进行轻量级封装

基本用法

{{bu-progress progress=60}}

type

    {{!--可根据type的类型，指定progress的呈现行为--}}
    {{bu-progress progress=40 type="success"}}
    {{bu-progress progress=20 type="info"}}
    {{bu-progress progress=60 type="warning"}}
    {{bu-progress progress=80 type="danger"}}

binding

{{bu-progress progressBinding="prog"}}
{{bu-button clicked="increment" content="Increment!"}}

也可以以对progress进行值的绑定

    Showcase.ShowComponentsProgressbarController = Ember.Controller.extend({
     prog: 0,
     incrementBy: 20,
     increment: function() {
       if (this.prog < 100) {
         return this.incrementProperty("prog", this.incrementBy);
       } else {
         return this.set("prog", this.incrementBy);
       }
     }
   });

progressbar 堆叠

    {{#bu-progress}}
    {{bu-progressbar type="success" progress="35"}}
    {{bu-progressbar type="warning" progress="20"}}
    {{bu-progressbar type="danger" progress="10"}}
    {{/bu-progress}}

可选的参数有
+ stripped 添加斜线样式 {boolean}
+ animated 是否添加CSS3样式 {boolean}