- Add proper Tracelog function to logging system. It should be possible
  for a test writer to send information to logs for further investigation.
  This would replace the current Log(time_t, char *fmt, ...) function
  in practice.

- If running tests with --in-proc option failing asserts 
  don't bail out from the test case as it should. Fix this. 

- Might be good idea to warn the user if runner is given command line
  options that doesn't make sense together. Cases such as using --xsl
  without --xml option or --iterations combined with --exec-key 
