Tab separation and span.

[XsFrozdY]

I would like to add the suggestion to add an option for how wide 1 tab-key-press adds, here on github it works fine, but on other places when pasting, its span's so wide that it's actually 3 tabs worth, I don't mid that being the default, but I'd like to be able to change it since it doesn't suit my needs and I don't mind pressing tab multiple times as long as it shows up as just 1 tab each time.

So an option to be able to set the span would be greatly appreciated.