CHANGE-709 - Refactor logging infrastructure (continuation)

CHANGE-709 - Refactor logging infrastructure (continuation from earlier changes)
- fix chicken/egg problem with log initialization
- add explicit logging messages in more places
- relocate log-delete code to logwriter
<a href='#crh-start'></a><a href='#crh-data-
Thanks.  I'm not sure why you would be getting a warning.  What PHP version are you testing against?  The shorthand is designed with `null` in mind:  http://3v4l.org/iQlQW