469.event hook tidy

Addresses #469

 * make event names (i.e. the config items) identical to the arg passed to handlers (the names used to have spaces, the args underscores - now both have hypens).
 * all events pass sensible messages to the handler
 * dropped the recent erroneous prepend of "execution" on a couple of event name args 
 * a test suite in dev/suites/events/ to test every event hook - will convert this to a reference test (the existing task events one is less comprehensive and does not check the args passed to handlers).