This TAP.lua implementation was upstreamed:
f9db364291
but it has not been released yet. It avoids hangs, and helps debug
hangs, on QuickBuild, so inline it until the next busted release.
Should provide some compatibility with old busted. And also removes duplicate
parts from successString and skippedString, making them more like failureString
and errorString which do not have times for technical reasons (busted for some
reason did not yet compute duration before running the relevant handlers).
Reasoning:
1. gtest is better then something like utfTerminal, yet it is way too verbose.
2. gtest cannot be configured to show colors always.
3. Actually I am going to add a CMake target which will allow running tests
(especially, functional tests) in parallel, but this is not going to work
well with any of the default output handlers. Build in this case must be more
or less silent, yet debuggable. New handler does not support this in this
commit though.
