Fix apply_text_layout
Fix apply_text_layout

The loop may never append an option tuple, when `end_offs` coincides
with the beginning of an `attr` element. (The loop potentially never
runs when `start_offs == end_offs == 0`.)

Fix by forcing another run in this case. Does not alter other behaviour,
because if the loop is executed without taking the `continue` branch,
the `end_offs <= aw.off+run` branch ensures that `aw.off != end_offs`.

urwid/urwid,wardi/urwid,wardi/urwid,urwid/urwid,inducer/urwid,inducer/urwid,wardi/urwid,urwid/urwid,inducer/urwid