Issue 388 - Console and NUnitLite reports

This PR fixes #388 and fixes #265. It includes:

* Bringing the two sets of reports as close together as possible.
* Porting improvements to  the color display from NUnitLite to the console and sharing the code.
* Adding tests for the reports.
* Making mock-nunit-assembly an exe that uses NUnitLite

The tests are minimalist and a bit fragile, but they will detect any changes in the output.

Having the mock assembly as an executable test provides a way of actually seeing the NUnitLite console runner work. Mock-nunit-assembly has failures and warnings and is a good test for the visual aspects of the output, so it's handy to be able to run it either via the console or directly.