Fix _.extend usage issue, which override defaults data

[aivus]

No description provided.

[coveralls]

Coverage remained the same at 51.38% when pulling 181a4d8 on fix-extend into 4550815 on master.

[s0ph1e]

Thanks 👍
Can you also fix same issues in tests?

[aivus]

Yeap. Already fixed.

[coveralls]

Coverage remained the same at 51.38% when pulling 4f4544c on fix-extend into 4550815 on master.

[s0ph1e]

I think it would be better to pass params directly to function, without extends.
Something like

scraper.scrape({
    url: 'http://example.com',
    directory: '/dir',
    .....
})

[s0ph1e]

@aivus what do you think?

[aivus]

I think we should leave defaultOptions like now. In the future, we can add to it required options.