Naming convention of directory name matching package and TRACE level

Apologies - two separate changes got mixed into this one branch:

* Update directory structure to include another subdirectory "slogger" such that the package name matches the directory name.
* Add a `TRACE` log Level below `DEBUG`.

Unfortunately the packaging change is backward incompatible with existing applications, but I think it's a one-time pain point that will provide a permanent foundation going forward.