Fix travis

This should fix the output problem with travis: Travis cuts the output after 10000 lines. Unfortunately, if I make the test setup completely quiet, travis thinks the test stalled after getting now output for 10 minutes. Therefore, now I just print every 100th line -- quite a dirty hack, but it seems to work.

I also added a coverage test. Nosetest will show coverage information now after every test, although I think this is not shown in github (but in the travis output).

Best,
  Matthias