First steps towards phase 0.5

This version uses TBB to run seperate tasks for each Stream when processing Events. Runs and Lumis are processed sequentially. The source, legacy modules and 'one' modules are serialized using mutexes. Further work needs to be done to make EventSetup access and delayed reads from the Source thread safe.

All framework unit tests pass (all of them are single threaded however). In principal, all single stream, single thread processes should run normally with this change.