[Gnash-dev] remoting

[strk]

preamble:

So, Jason drafted AMF-based remoting and I'm helping cleaning it up.
NetConnection.call() is currently the only user for the new non-blocking
read interface of IOChannel.
This was done to avoid threading there.

issues:

- Jason used an interval of 500ms (1/2 second) between non-blocking
  reads. No wonder it takes almost an hour to fetch streets from 
  openstreetmap (potlatch). Making quicker ticks should improve things
  a lot. Ideally, the 'ticker' should be waken up from an FD checker
  which would select with a timeout.

- We need to distinguish between 404 (not found) and empty responses
  from HTTP. IOChannel still has a get_error() method which may be
  used, or we may use the exception interface. If we opt for the latter
  we should catch on every read. What do other devels think about it ?

- A different approach might be using a thread (a single thread for
  each NetConnection used for remoting). In this case we'd have the thread
  using blocking reads (which would select() internally).

--strk;