- fixed issue w/ outer surface materials

Support for multi-threaded Geant4 applications using DDG4Details are described in the release notes.

use map(string, string) to store parameter value pairs, declareProperty so we can pass it from python as a dict
call saveRun from endRun

 Added a new AHcal Barrel sensitive tiling driver - TiledLayerGridXY in DDSegmentation for AHcal Barrel Sensitive layer segmentation design.

  as using direct access always requires runNum==0 and sequential evt nums ...

    - ICone, VolConeImpl, VolCone, ConeSurface
    

  ( innerThickness, innerRadLength, etc)

Fix typos in DDG4 manual, correct the Sigma entry for VertexSmear, add Mask, change Mask type to int.bitmask everywhere

DDG4.py Output2ROOT: Only add '.root' extension if it is not already present. Consistent with lcio output