update to c++ style include header syntax

examples/COUPLE/lammps_quest/lmpqst.cpp

examples/COUPLE/lammps_spparks/lmpspk.cpp

examples/COUPLE/library/error.cpp

examples/COUPLE/library/files.cpp

examples/COUPLE/library/irregular.cpp

examples/COUPLE/library/lammps_data_write.cpp

examples/COUPLE/library/lammps_data_write.h

examples/COUPLE/library/many2many.cpp

examples/COUPLE/library/many2one.cpp

examples/COUPLE/library/memory.cpp

examples/COUPLE/library/one2many.cpp

examples/COUPLE/library/send2one.cpp

examples/COUPLE/multiple/multiple.cpp

examples/COUPLE/simple/simple.cpp