HH-43534 changes for tornado3 upgrade
HH-43534 remove apps option
Merge remote-tracking branch 'origin/HH-43534' into EXP-11489
release 2.19.18 [an.sumin@hh.ru]
HH-43961 improve tests
HH-40165 add preprocessors
HH-40165 update docs and misc
Merge remote-tracking branch 'origin/HH-43961' into EXP-11504
Merge remote-tracking branch 'origin/HH-40165' into EXP-11504
release 2.20.0 [an.sumin@hh.ru]
tornado-3 fix send_error
update to new tornado_util and other new tornado fixes