增加对文件夹上传的支持

[muzea]

这边还有俩问题，

1. 目录上传的单测不会写
2. readEntries file 这些api其实是异步回调的，很难把目录下的文件合并到一次上传中，只能一个文件传一次

[coveralls]

Coverage increased (+3.06%) to 84.252% when pulling 01fff02 on muzea:master into ea90bdd on react-component:master.

[afc163]

这个 judge 的意思是？

[muzea]

因为这个地方有个accept属性，过滤下不符合的文件

[afc163]

可以把命名修改的更语义化一点。

[muzea]

或许这个变量叫做 isAccepted 会好点？

[muzea]

我明天看下这边单测怎么写，补一下吧

[muzea]

终于绿了（

还有点小问题，如果测试目录上传成功的话，会有报错，测试代码如下

  ● uploader › directory uploader › upload success

    Timeout - Async callback was not invoked within timeout specified by 
jasmine.DEFAULT_TIMEOUT_INTERVAL.

    it('upload success', (done) => {
      const input = TestUtils.findRenderedDOMComponentWithTag(uploader, 'input');

      const files = {
          name: 'foo',
          children: [
              {
                name: 'foo.png',
              },
            ],
      };

      handlers.onSuccess = (ret, file) => {
        expect(ret[1]).to.eql(file.name);
        expect(file).to.have.property('uid');
        done();
      };

      handlers.onError = (err) => {
        done(err);
      };

      Simulate.drop(input, { dataTransfer: { items: [makeDataTransferItem(files)] } });

      setTimeout(() => {
        requests[0].respond(200, {}, `["","${files[0].children[0].name}"]`);
      }, 100);
    });

[afc163]

This resolved ant-design/ant-design#7315