Nunit now handles inconclusive tests and marks them with yellow mark

Also, when a feature contains inconclusive tests only, it itself is marked with yellow mark.

Other changes:
1. Added regenerated example files for xunit and nunit and updated tests for parsers.
2. Added a flag to TestResult - it was needed for testing, since without it I could not know whether I'm getting inconclusive case because the test itself is inconclusive, or because the test was not found inside the file at all.
3. I looked at not implemented steps in nunit specflow adapter, but it looks like SpecFlow marks not automated tests as failing instead of inconclusive... So could not add the support there. MsTest supports inconclusive tests by not including them inside the report at all lol :-). They got a bug logged on it, so maybe in the near future this will have to be revised in the parser.