Minor comment and formatting cleanup.
Moved mainDir var to logging._mainDir, and changed it to use the cwd if running in an interactive session.
Created Context#attachToHandler, which replaces the 'ConsoleContext' constructor in ConsoleHandler#onMessage, and changed BaseHandler and Dumper to use it.
Created the Context#shortDatetime property, and changed the console handler to use it.
Added util/stack, and used it to create the type, func, filename, line, and column properties of Context.
Updated ConsoleHandler.prototype.format to show the filename, line, and column of the code that logged each message.
Added BaseHandler#level property to handle setting level with either strings or numbers.
Reworked initLogLevel so that it correctly sets function names.

(since you can't assign to func.name)
Corrected reversed .join() call for levels in error message.
Expose Dumper and Logger so calling code can inherit/modify them.