convert gpu lib to use c++-style include files

lib/gpu/cudpp_mini/cudpp.h

lib/gpu/cudpp_mini/cudpp_plan.cpp

lib/gpu/cudpp_mini/cudpp_util.h

lib/gpu/geryon/nvd_macros.h

lib/gpu/geryon/ocl_macros.h

lib/gpu/lal_answer.h

lib/gpu/lal_atom.h

lib/gpu/lal_balance.h

lib/gpu/lal_beck_ext.cpp

lib/gpu/lal_born_coul_long_ext.cpp

lib/gpu/lal_born_coul_wolf_ext.cpp

lib/gpu/lal_born_ext.cpp

lib/gpu/lal_buck_coul_ext.cpp

lib/gpu/lal_buck_coul_long_ext.cpp

lib/gpu/lal_buck_ext.cpp

lib/gpu/lal_charmm_long_ext.cpp

lib/gpu/lal_colloid_ext.cpp

lib/gpu/lal_coul_debye_ext.cpp

lib/gpu/lal_coul_dsf_ext.cpp

lib/gpu/lal_coul_ext.cpp