Change logging handler to be compliant with behavior before java_logging
feature commit (91e93be).

Before, standard and error output was used and give information of
Fitnesse server status.
Now, with Java logging, the output used is always System.err.

Other applications as "Jenkins Fitnesse plugin" wait for something in
the standard output.

I've created a new JUL Handler which writes in Sytem.out all logs with
level < LEVEL.WARNING, others goes to System.err.

(Test with "Jenkins Fitnesse plugin":
https://github.com/jenkinsci/fitnesse-plugin/blob/master/src/main/java/hudson/plugins/fitnesse/StdConsole.java)
Remove duplicate new lines in logs
Format code
Change test to be compliant with method name
Add a test to ConsoleHandler