Cleans up use of loggers

Includes moving the configuration of `wrapper.log` out of the modules
and into the examples, and ensuring consistent reasonable use of
appropriate dotted-path logger names.

Also modifies example to use the charcoal sandbox and a main() function.

resolves #41
Adds a .text_content property to Event.

resolves #44
Merge branch 'text-content' into upstream-test