Fix [-Wrange-loop-construct] compilation warnings from clang10
Fixes warnings like:
warning: loop variable 'tkMCP' of type 'const Relations::WEntry_<LHCb::Track *, LHCb::MCParticle *, double>' creates a copy from type 'const Relations::WEntry_<LHCb::Track *, LHCb::MCParticle *, double>' [-Wrange-loop-construct]
for ( const auto tkMCP : tkMCPs ) {
^
Also, flyby cleanup up CMakeLists.txt to suppress Boost and ROOT compilation warnings
@jonrob FYI
Edited by Marco Cattaneo