* Header now contains (src, dst) context IDs for routing.
* econtext.context_id now contains current process' context ID.
* Now do 16kb-sized reads rather than 4kb.
* econtext package is uniformly imported in econtext/core.py in slave
and master.
* Introduce econtext.core.Message() to centralize pickling policy, and
various function interfaces, may rip it out again later.
* Teach slave/first stage to preserve the copy of econtext.core sent to
it, so that it can be used for subsequent slave-of-slave bootstraps.
* Disconnect Stream from Context, and teach Context to send messages via
Router. In this way the Context class works identically for slaves
directly connected via a Stream, or those for whom other slaves are
acting as proxies.
* Implement Router, which knows a list of contexts reachable via a
Stream. Move context registry out of Broker and into Router.
* Move _invoke crap out of stream and into Context.
* Try to avoid pickling on the Broker thread wherever possible.
* Delete connection-specific fields from Context, they live on the
associated Stream subclass now instead.
* Merge alloc_handle() and add_handle_cb() into add_handler().
* s/enqueue/send/
* Add a hacky guard to prevent send_await() deadlock from Broker thread.
* Temporarily break shutdown logic: graceful shutdown is broken since
Broker doesn't know about which contexts exist any more.
* Handle EIO in iter_read() too. Also need to support ECONNRESET in here.
* Make iter_read() show last 100 bytes on failure.
* econtext.master.connect() is now econtext.master.Router.connect(),
move most of the context/stream construction cutpaste into a single
function, and Stream.construct().
* Stop using sys.executable, since it is the empty string when Python
has been started with a custom argv[0]. Hard-wire python2.7 for now.
* Streams now have names, which are used as the default name for the
associated Context during construction. That way Stream<->Context
association is still fairly obviously and Stream.repr() prints
something nice.
David Wilson