* v test: support for running 'v test folder/' .
* Support passing multiple folders and also single _test.v files to 'v test' .
* Update vhelp too, with descriptions of v test folder/ and v -stats .
* Fix running `v test v` from outside the root of the v tree.
* Draft implementation of `v -stats file_test.v` .
* compiler: call stuff in vlib/benchmark/tests/always_imported.v, when doing `v -stats file_test.v`
* Nicer looking output from 'v -stats file_test.v' .
* Tweak colors and layout of -stats file_test.v .
* Fix a hardcoded path in compiler/main.v .
* Show colorized OK/FAIL for the examples in 'v test v' too.
* Add some comments about the purpose of the methods inside vlib/benchmark/tests/always_imported.v .
* when fails are 0, do not colorize their number at all.
* Update CONTRIBUTING.md with workflow example
Added [@spytheman's example](https://discordapp.com/channels/592103645835821068/592106336838352923/627559453788733440). Please review @spytheman and @medvednikov with any improvements or updates and clarifications! :) Hope this helps. I'm sure I can make things a little more consistent or improve formatting a little, but I wanted to get this at least somewhere where we won't forget to share it.
* Update CONTRIBUTING.md
Additional tweaks as per comments.
* tools/performance_compare is now more robust. It uses the C source from the time of the v commit, instead of always the latest one. It also now clones https://github.com/vlang/vc just once per comparison, not for every build.
* Remove obsoleted tools/compare_v_performance_between_commits shell script.
