Merge pull request #40 from Manishearth/test

Forward test to master: adding Event class
Allow more test branches in case we need to avoid clashes
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