Expected failures are now treated as skipped tests

Before they were being treated as "passing" tests.
Since this might cause them to be silently ignored, classifying them
under "skipped" will ensure they won't go unnoticed.

Expected failures != skipped. The former will always be executed.

test/simpletap/__init__.py

@@ -148,7 +148,7 @@ class TAPTestResult(unittest.result.TestResult):
                 )
             elif status == "EXPECTED_FAILURE":
                 self.stream.writeln("{0} {1} - {2}".format(
-                    color("ok", "green"), self.testsRun, desc)
+                    color("skip", "yellow"), self.testsRun, desc)
                 )
             else:
                 self.stream.writeln("{0} {1} - {2}".format(