QPID-4967 - Work in progress on multi-router networks
 - Added a feature to the hash table to allow referenced objects to hold a direct linkage
   back to the hash structure for fast deletion and access to the key.  This allows the key
   to be stored in only one place and allows items to be removed without requiring a hash
   lookup on the key.
 - Completed the integration of the Python router and the C data structures that track
   remote routers (neighbor and multi-hop).
 - Allow multiple addresses in the ioAdapter from Python.
 - Added a separate address for the hello messages because the messaging pattern is different
   for these messages.
 - Added some content to the TODO file.
 - Added test configurations for a two-router network.


git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1529163 13f79535-47bb-0310-9956-ffa450edef68