Avoid bleeding sensitive information into logs.

This is more a request for comment than a pull request.

I found a lot of private information was bleeding into the logs. More specifically username and passwords.
Since I have a lot of servers, I also use a shared logging solution, so I'm a little bit skeptical about seeing passwords in my logs.

This patch addresses this issue partially. There is a lot more work that needs to be done, and before doing this, I would like to know what you think about my proposals.

The real solution IMHO would be to avoid passing strings around, and rather pass URL's but that's a rather intrusive refactoring. I address this currently by providing an advanced option which allows insecure logging, (not exposed in advancedsettings.xml), and removing data in strings, which are assumed to be URLs.

Please advice if this is a path to be followed, before I do more work on this.