Changes:
- wait control sequence for end of bracketed paste (and only after, check if
we should ask confirmation to user)
- add option weechat.look.paste_bracketed_timer_delay to force the end of
bracketed paste if the control sequence for end of bracketed paste was not
received in time
- in bracketed paste mode, with paste_max_lines=1, do not ask confirmation for
one line (ask for one line only if paste_max_lines=0)
- fix bugs with mintty: bracketed paste should be ok every time (even if some
codes are sometimes partially received, WeeChat will now handle that properly);
the standard paste often fails (due to bug in mintty, which sends paste very
slowly to remote app); so the bracketed paste mode is highly recommended with
mintty
- after paste in bracketed paste mode, the undo key (ctrl+"_" by default) will
undo whole paste, not chars one by one
