HH-45022 override check_xsrf_cookie method of PageHandler
Merge remote-tracking branch 'origin/HH-45022' into EXP-11855
release 2.20.16 [a.inozemtsev@hh.ru]
Merge remote-tracking branch 'origin/HH-45117' into EXP-11891
release 2.20.17 [an.sumin@hh.ru]
HH-45117 fix HTTPError in prepare method
Merge remote-tracking branch 'origin/HH-45117' into EXP-11891
release 2.20.18 [an.sumin@hh.ru]
HH-45307 fix calling template_postprocessor after HTTPError
HH-45307 add send_error implementation for backwards compatibility
tornado-3 fix send_error