Two suggested improvements

One year after discussing, finally I managed to access GitHub to make the suggested change.

- ContainsIgnoreCaseValidationMatcher: this is really a bug. The change is just a few characters in line 31 - I don't know why Git thinks that I have replaced the whole file.

- TestCase: some suggestion to add variables that can be used in logging.

(Other custimizations I have made can be proposed only after we have upgraded to Citrus 1.3, as there have been too many architectural changes...)