Various small fixes:

Various small fixes:

- Correct polarity for pA/Ap collision w/DPMJet
- Add possiblity to do Fast simulation (generator only) using
  the configurations here.   The simulation is implemented as a
  TSelector which allows us to execute the fast simulation in
  Proof(Lite) for better performance.  The script RunFast.C takes
  care or running the simulation given simple arguments:
  - Proof or not proof
  - Run number to 'anchor' in - really this is only used to look
    up the relevant beam parameters from OCDB/GRP
  - Optional impact parameter range
  - Optional Event generator to use
  - How often to get back monitor histograms (or not at all)
  - Initial go at a VirtualTrain class for QA and AOD (not used)
  - Clean up library loading in BaseConfig.C