Print summary at end of running tests with statistics print

[SSoelvsten]

When printing statistics in our unit tests it is very hard to see whether they parsed or not. If statistics are turned on, we ought to do a nice summary printing below of whether the unit tests passed or not.

• [ ] Pretty print in green when unit tests have passed.
• [ ] Pretty print in red with the number of unit tests failing.

Alternatively, if unit tests have failed, then don't print statistics (or just print them to a string, not std::cout.