new Trace addition for Tango, plus log.format()

[Mark Wrenn]

Thanks for this.  Love the logging architecture BTW.  Nice work.

Kris wrote:
> There's been some new developments here today. While Tango has always had a 
> robust logging package reminiscent of Log4J, a lot of folk tend to use 
> Stdout or Stderr instead. To better support the needs of simplistic debug 
> tracing, a dedicated module has been added: