* Print error messages to stderr.
It makes it possible to redirect output to /dev/null and see only the
failed tests.
* Show an error message if we failed to find the queries dir.
* Treat 'distributed' and 'global' the same way as 'shard' in test names.
Some tests that need to run distributed queries do not use the
'shard' marker. It seems easier to support another two markers than
to rename the tests.
* CLICKHOUSE-4063: less manual html @ index.md
* CLICKHOUSE-4063: recommend markdown="1" in README.md
* CLICKHOUSE-4003: manually purge custom.css for now
* CLICKHOUSE-4064: expand <details> before any print (including to pdf)
* CLICKHOUSE-3927: rearrange interfaces/formats.md a bit
* CLICKHOUSE-3306: add few http headers
* Remove copy-paste introduced in #3392
* Hopefully better chinese fonts #3392
* get rid of tabs @ custom.css
* Apply comments and patch from #3384
* Add jdbc.md to ToC and some translation, though it still looks badly incomplete
* minor punctuation
* Add some backlinks to official website from mirrors that just blindly take markdown sources
* Do not make fonts extra light
* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's//g' {}
* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's/ sql/g' {}
* Remove outdated stuff from roadmap.md
* Not so light font on front page too
* Refactor Chinese formats.md to match recent changes in other languages
* Added documentation about ClickHouse testing (draft) [#CLICKHOUSE-2]
* Updated documentation about ClickHouse testing [#CLICKHOUSE-2]
* Moved information about ClickHouse tests to correct place [#CLICKHOUSE-3]
* Moved information about ClickHouse tests to correct place [#CLICKHOUSE-3]
