Change logging format

[tmaier]

Polipus: [worker #2] Page [http://www.example.com/89237459832475] downloaded

in iTerm 2, I can CMD+click on the link. But it then tries to open http://www.example.com/89237459832475%5D.

Therefore, I suggest to change the log message to

Polipus: [worker #2] Page (http://www.example.com/89237459832475) downloaded

or

Polipus: [worker #2] Page <http://www.example.com/89237459832475> downloaded

I could provide a pull request if you want

[taganaka]

Works for me :+1: