change the fluids main to call if needed the radiation model for  - initialisation  - eigenvalue solve  - time solve  - cleanup at end
change the fluids main to call if needed the radiation model for
 - initialisation
 - eigenvalue solve
 - time solve
 - cleanup at end

two allocatable radiation data types are also declared at the top 
associated with the radiation materials database and interpolation 
instructions

this is actually needed for the previous commit to make it compile



jjo31/ATHAM-Fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,rjferrier/fluidity,jrper/fluidity,jrper/fluidity,iakovos-panourgias/fluidity,rjferrier/fluidity,rjferrier/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,jjo31/ATHAM-Fluidity,iakovos-panourgias/fluidity,iakovos-panourgias/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,jrper/fluidity,rjferrier/fluidity,jjo31/ATHAM-Fluidity