Fussy about separator line lengths.
Rearranged logging.js, and added lots more doc comments.
Corrected indentation of the logging module's contents.
Simplified `strformat`'s exports, and renamed the function to match elsewhere.
Added lib/HasLevel.js, and reworked Context, Logger, and BaseHandler to use it.
Fixed @module jsdoc directives.

Now, we don't have a bunch of extra modules listed that we don't need, and the ones we do need actually get docs generated.
Changed Context, Dumper, Logger, and the handlers to export their classes directly instead of having an extra level of nesting.
Reworked Logger's log level method creation, and added doc comments for the methods.
Added `silence()` and `unsilence()` to the logging module, and added `silence()`, `unsilence()`, and `silenced` to logging.Logger and logging.handlers.Base.
Removed Logger#walkHierarchy and added Logger#accumInherited.

This is simpler, and much faster.
Updated doc comments in Logger, and changed Logger#log to return `this`.
Removed the last vestiges of Logger.loggerNamesSorted, since we no longer need it.
Updated logging.getLevel() and logging.getLevelIdx() to take either a name or index, and updated their doc comments.
Updated Logger#log() to use this.levelIdx instead of this.level.
Removed unused Context#clone().
Changed Context to take `levelIdx` instead of `level`.
Correct bug with Dumper never rendering in color when passed as the first arg to log().
Simplified implementation of Context#attachToHandler() using Object.create().

Also, updated doc comment.
Added doc comment to logging.handlers.Console.
Added BaseHandler#toString, to ease debugging.