The new @Polymorphic annotation serves the exact same purpose as
@Event(includeSubtypes = true), but should be easier to read in complex
handler declarations. It has to be used in conjunction with the @Event
annotation, not instead of it.
event-bus is now a parent project containing the two modules
event-bus-core (the previous event-bus) and event-bus-ap (annotation
processor).
The version of the parent project (and thus that of the modules) has
been bumped to 1.0.0, as this change breaks compatibility with previous
versions due to the different artifact, module and package names.
