partial merge japan

	modified:   input/input_example.dat
	modified:   src/bc.f90
	modified:   src/electrostatics.f90
	modified:   src/makefile
	modified:   src/particles.f90
	modified:   src/post.f90
	new file:   src/writedat_fluid_xy.f90
	new file:   src/writedat_fluid_xz.f90
	new file:   src/writevtk_fluid_xy.f90
	modified:   src/writevtk_fluid_xyz.f90
	modified:   src/writevtk_fluid_xz.f90
	modified:   src/writevtk_fluid_yz.f90