Backspace with nothing before becomes delete

[ewaters]

Non-intuitively, Term::Readline::Zoid makes the backspace key act like the delete key if there's no characters before the prompt.

[supervacuo]

On a similar note, Ctrl+<left/right arrow key> doesn't have the expected readline behaviour (i.e. skipping to the next / previous word); sometimes it's interpreted as "delete", sometimes nothing.