Replace bullets by check boxes in README.

[kdexd]

This should really help to keep a track of papers read so far. I would love to fork the repo and keep on checking the boxes in my local fork.

For example: Have a look at this section. People fork this repo and check the boxes as they finish reading each section.

[Anirudh257]

I think I can try working on this.

[muhdhisham]

Can I take up this issue ?

[gzbin365]

您好，邮件我已经收到了，我会尽快处理。