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.
