Add a rough and ready indication of which tests failed

[nhemingway]

Stefan,

I got annoyed not having a summary of which tests failed at the bottom, so added one.

It may be better in the long term to build/hook into a unit test framework that supports test suites and reporting, and all the other xUnit like features, but my tcl foo is not strong enough for that

[landro]

Thanks @nhemingway - I've wanted to get in some kind of functionality like this for a long time! xUnit sounds like a great future improvement. Not wure what XML support looks like in tcl, but at least the XML format in xunit is not too complex, so it should be doable.
Sorry it took me so long to get this PR in. I was extremely busy before summer, and then I went on vacation for like 4 weeks.