Track events that occur in the module system abstractly.
A concrete implementation can provide localized messages
for these, notify the user visually, track performance, etc.
Only events relevant to the user or to performance need to
be logged; detailed low-level descriptions of what is
happening can simply be logged to the ErrorManager.
author: Jesse Glick
Log an event.
You must pass a fixed event type string, and a list
of arguments (meaning varies according to event type).
Note that the event type string must be the exact String
listed as the constant in this class, not a copy.