Implicit pausing MiniAxon

Consider a version of Axon where microprocesses pause by default after each iteration of main. Such a setup encourages the writing of efficient components by making polling difficult (but not impossible - a clock/tick threadedcomponent could send a wakeup message every second). This removes the ideas of pausing and unpausing - activate() can be used instead of unpause().

I also have different ideas about trigging the activation/unpausing of components. The component should be able to specify events that wake it. For inboxes, the receipt of a message could wake the parent component, or not. For outboxes, the removal of a sent message from the recipient inbox (through recv()) could also wake the parent.

There are occasions when you would not want delivery to an inbox to wake the component:
Consider this component:

class Combiner(component):
  Inboxes = ["a", "b"]

  def __main__(self):
      while 1:
          while self.dataReady("a") and self.dataReady("b"):
              newmsg = [self.recv("a"), self.recv("b")]
              self.send(newmsg, "outbox")
          yield 1

It waits until both inbox A and inbox B have at contain one message each, takes the first (oldest) message from each, combines them into a two-element list and sends that list on.
If A contains messages, but B contains none, the Combiner is waiting for B. The addition
of messages to A does not merit waking the component - it won't be able to do anything more than it could do before.

Syntax such as:

self.wakeOn("b")

could be used to accomplish this selectiveness.