contructors/limiters
			--------------------

    This directory contains "technical" constructors in the sense they do not
add processes with physics content but add processes or modify physics lists to
allow for step limitation in parallel geometries, biasing, etc.


G4FastSimulationPhysics:
------------------------

    Constructor that modifies a given physics list to allow for fast simulation.

    One, or several, G4FastSimulationManagerProcess objects are added to the
    process manager of particles for which a fast simulation is requested.
    
    The fast simulation may be associated to regions in the mass geometry, in
    what case a call like fastSimPhys->ActivateFastSimulation("e-") must be
    done to allow for fast simulation of electrons.
    Parallel geometries can be used also in what case the geometry is specified
    by its name like fastSimPhys->ActivateFastSimulation("e-","parallelGeom") to
    allow for fast simulation of electrons, with fast simulation models attached
    to regions in "parallelGeom".


G4GenericBiasingPhysics:
------------------------

    Constructor that modifies a given physics list to allow for generic biasing.

    It provides three type of functionnalities:
        - wrap physics processes with G4BiasingProcessInterface processes to
	  make the generic biasing to control them (allowing change of
	  interaction law, change of final state generation).
	- add G4BiasingProcessInterface processes, but without wrapping a
	  physics process, in what case these processes will be used for
	  "non-physics based biasing" : ie, spliting and killing
        - add G4ParallelGeometriesLimiterProcess process (at most one per
	  process manager) that provides step limitation on the parallel
	  geometries used in generic biasing. A process can handle several
	  parallel geometries associated to one particle type.
	  
    Various methods are provided to activate these functionnalities per
    particle, set of particles, to activate physics-based only or
    non-physics-based only or both functionnalities, and to activate the
    parallel geometry functionnality.
    This is documented in include/G4GenericBiasingPhysics.hh .


G4ImportanceBiasing:
-------------------

G4MaxTimeCuts:
--------------

G4MinEkineCuts:
---------------

G4NeutronTrackingCut:
---------------------

G4ParallelWorldPhysics:
-----------------------

G4SpecialCuts:
--------------

G4StepLimiterPhysics:
---------------------

G4WeightWindowBiasing:
----------------------