Comment #3 on issue 643 by pekka.klarck: [Jython] UnicodeDecodeError in OperatingSystem.List Files In Directory when File contains Umlauts
http://code.google.com/p/robotframework/issues/detail?id=643
We should probably also make sure os.listdir gets a Unicode string as an argument. Normal test data comes in as Unicode so typically that's the case, but it is possible to pass a path in also as a variable and then it could be Python str or Java String.
