Modernize DetDesc

• prefer implicit, compiler generated destructors
• remove obsolete SVN/CVS identifiers
• factor out instance counting into a dedicated base class
• prefer direct member initialization
• change LogVolBase::insideDaugther so that it does not expose the internal comtainer type
• prefer std::unique_ptr
• hide container type in SolidBoolean -- return an range of children, which, when dereferenced, yields a (const) reference
  • deprecated 'childBegin' and 'childEnd'
• remove previously deprecated functions
• remove deprecated std::unary_function, std::binary_function
• prefer auto
• remove commented out old code
• prefer switch over if-then-else-if cascades