- Separate method pointers (i.e., the vtable) in the various classes into
  separate "class" structs (think klass in Gtk). Right now these waste
  space because they're allocated with every instance, but since they're
  not used extensively it hasn't really been worth it so far.

- The init methods must be allowed to fail. Currently allocations in that
  method can fail but this failure can not be signaled to the caller.

- Add an error variable so the user has a way to figure out what happened
  when things go wrong.

- Add support for at least a small number of expressions -- needed in
  bro_attr.[ch].

- Add support for tables/sets.

- Add a server-suitable API, i.e., how can one write an application that
  listens on a given port, using Broccoli.

- When configure determined that lex+yacc exist, make clean doesn't clean
  up the generated lexer/parser C files. I presume this is because I keep
  them all in EXTRA_DIST. Ensure make clean removes the generated files
  when we know we can regenerate them.

- There's a segfault lurking in __bro_record_get_nth_val() with records
  that don't have all members assigned to. Investigate whether dummy
  val approach really works or whether it's a design flaw.