Clean up of the material manager... Removal of duplicated & unused code

...oModelFuncSnippets/GeoModelFuncSnippets/MaterialManager.h

GeoModelCore/GeoModelFuncSnippets/src/MaterialManager.cxx

...elCore/GeoModelKernel/GeoModelKernel/GeoMaterialManager.h

...lCore/GeoModelKernel/GeoModelKernel/IGeoMaterialManager.h

GeoModelCore/GeoModelKernel/src/GeoMaterialManager.cxx

GeoModelTools/GeoModelXML/GeoModelXml/GeoModelXml/GmxUtil.h

...ols/GeoModelXML/GeoModelXml/GeoModelXml/MaterialManager.h

GeoModelTools/GeoModelXML/GeoModelXml/src/AddPlane.cxx

GeoModelTools/GeoModelXML/GeoModelXml/src/Gmx2Geo.cxx

...odelTools/GeoModelXML/GeoModelXml/src/MaterialManager.cxx

...lTools/GeoModelXML/GeoModelXml/src/TransformProcessor.cxx