Modernize LHCbKernel

• prefer implicit destructors
• prefer forwarding constructors to base-class
• prefer struct in case all class member data/functions are public
• add final
• drop deprecated std::binary_function, std::unary_function
• prefer non-templated functor structs with templated operator()
• prefer emplace_back over push_back
• prefer STL algorithms over raw loops
• explicitly reserve std::vector sizes prior to push_back/emplace_back
• avoid temporary copies -- prefer remove_if over copying
• speed up LHCbID::channelID by making sure detectorType() is only called once