Bug: emulateTabFrom(source).toPreviousElement() can't find previous element

[aaronnuu]

Hello, this library seems to be exactly what I need for my use case, I just have found one issue when running emulateTabFrom(source).toPreviousElement() where instead of tabbing from the source it will tab from the document.body instead.

Thanks very much for looking into this, if I am mistaken and this is not the intended behaviour then it would be great if you could help me figure out how to tab previous from a specific element using this library.

I have a PR here: #22 to fix this issue.