The code that handles the Avro files is now fully abstracted behind the
AvroConverter class that implements the RowEventHandler interface.
The code still has some avro specific behavior in a few places (parsing of
JSON files into TableCreate objects). This can be replaced, if needed, by
querying the master server for the CREATE TABLE statements.
The RBR event handling related objects are now all in the rpl_events.hh
header. The intention is to combine all replication processing related
events used in the binlogrouter and avrorouter into this header to make
them reusable.
Also fixed the TableCreateEvent constructor to use an rvalue instead of
stealing an lvalue.
