Fix issue where tapping backspace to delete a single letter also selects the previous token

[joeldrotleff]

This is a fix for an issue I noticed on iOS 10. I have not tested it for iOS 9 or 8.

[joeldrotleff]

Tested and looks good on iOS 9

[rsattar]

Thank Joel!

Almost everything works here. The only issue I'm seeing is that, at least on iOS 8, you can no longer invoke delete on an empty text field to highlight the previous token (like you can in the system picker on iOS).

Looking into whether I can tweak your changes to make that work. I understand that iOS 8 is likely in low usage now, but I'd like to keep support for it, if possible.

[joeldrotleff]

@rsattar Ok deleting definitely works in iOS 10, pretty sure also in iOS 9. For my company, iOS 8 usage is down to a bit over 1% so I'm realistically not going to fix it - but I suspect conditionally going back to the previous behavior would fix the delete issue.