Remove System.out.println() calls and replace them with Loggers in the sharelibs

Currently there are a lot of System.out.println() calls in the code, mostly in the sharelib.

This solution is inferior to using a logger library, where we can fine-tune a lot of different things. It's desirable that we migrate these calls to a logging framework.

The preferred solution would be to use a Logger in our code, redirected per default to the console using ConsoleAppender. That way we wouldn't be breaking compatibility, but some of the users could redirect to another Appender s.