Update the session store to use the Role-Of-Node and Node-Functionality to distinguish sessions
Unit test for session store changes
Update Messge to hold the Role-Of--Node and Node-Functionality for lookups
Extract Role-Of-Node and Node-Functionality from JSON
Pass RoN and NF to store
Improve the opaque data for INTERIM timers
Merge pull request #15 from Metaswitch/better-session-corellation

Reviewer Mike - Better session corellation