modified:   include/DDRec/CellIDPositionConverter.h
modified:   src/CellIDPositionConverter.cpp

 - add all parentless particles to outgoing vertex

Add notes that where missing

Beam pipe driver modified, and additional field (with default value) added, that controls the placement of the core (made of beam material), in order to be able to add several BP walls made of various materials

if the macro is called from other libraries this variable might be set and should be used for consistency