Fixed #89 (tearDown() not called when exception is thrown and abortTestOnFail is set)

Fixed by restricting the effect of TS_ABORT to TS_XXX macros. TS_ABORT should not be called on an upper level because this causes the following negative effects:
- the entire test stops (world)
- tearDown() are not called neither for test cases nor for test suites which may result in resource leaks