Add some empty lines for linter sake. For #207

[eleksir]

No description provided.

[eleksir]

Some newlines here and there. It is sometimes enhances readability, but not in all cases.
Say, it is good practice separate var declarations and strings with '=' operator, but if you have mixed strings it can look weird.
Anyway, I also add some empty lines before and after "for{}", before and after 'switch{}', between "case:", before "default:", before and after "if{}" if it is not "if err != nil{}", etc. It comes from perl-folks from my current job and looks convenient.

[mdosch]

I find stuff like this looking awkward:

n, err := d.w.Write(data)

	if err != nil {
		return n, err
	}

Personally I like the style of gofumpt. Maybe there are some different styles to choose from?