split title with _

[deweydu]

1. I found some sites contained underscore in title section, so I think we add split title with undersocre for good.
2. Usually, we just want to download one category, instead of all categories.

[codelucas]

I like your title splitting by underscore change but I don't understand the category change.

Usually, we just want to download one category, instead of all categories.

How do you know that? Could you update this PR to remove that commit?

[deweydu]

Hi Lucas,

I have remove that commit, and left the title splitting by underscore.

Thanks :)

[codelucas]

👍