[c++ 0-9 branch] Latest commits.

[Alan Conway <ac...@redhat.com>]

Andrew: I've got your latest on the branch with my latest, I've
separated MessageHandlerImpl into it's own files so it should be easier
to merge going forward.

See the svn log for details but main thrust of my latest changes is to
make the broker::Channel responsible for handling frames rather than the
Connection. Since every frame has a channel number, every frame can be
directed to a channel. Channel objects are created the first time a
frame mentions their number, the channel objects themselves will keep
track of whether they have been open()ed or whether they are/are not the
special channel 0 and work or throw exceptions accordingly.

The reason for all this is request/response handling is per-channel,
even for channel 0 so we need a channel object to handle every frame.

The code has lots of irrelevant leftovers, funny class names and FIXMES
but its going in the right direction. Will clean up and do the client
side tomorrow. Part of the current changes have increased broker/client
symmetry - both sides will use the same BodyHandler base class to manage
request/response.

Cheers,
Alan.