Improve Jingle logging using commons-logging
Add a new logging wrapper class that uses commons-logging if available in the classpath, otherwise fallback to System.out/err.print(). Also significantly improve the substance of logging in Smack/Jingle using this new logging class.
Improved the logging around Jingle. It's now much clearer what's going on. Also added a new SmackLogger class that allows Smack/Jingle to take advantage of commons.logging to give much better control over where the logs go.