some clean up of outcommented old lines

src/data/macros.h

src/data/simparticles.h

src/domain/domain_balance.cc

src/domain/domain_exchange.cc

src/domain/domain_toplevel.cc

src/io/io.h

src/lightcone/lightcone_massmap_io.h

src/mergertree/io_halotrees.cc

src/mergertree/mergertree.h

src/mpi_utils/generic_comm.h

src/mpi_utils/healthtest.cc

src/mpi_utils/sizelimited_sendrecv.cc

src/sort/cxxsort.h

src/subfind/subfind_history.cc

src/time_integration/timestep_treebased.cc

src/tree/tree.cc

src/tree/tree.h