HH-44762 add tests for singleapp mode
HH-44762 remove some unneccessary stuff
HH-44762 fix singleapp test configs
HH-44762 singleapp in example_app
HH-44762 update docs
HH-44762 fix unicode test
Merge remote-tracking branch 'origin/HH-44762' into EXP-11754
release 2.20.11 [an.sumin@hh.ru]
tornado-3 fix send_error