u_phi in the fluid is zero (no sh-waves), although

the phi component of the gradient of chi is not zero. Proof: MvD aniso notes, p. 28.1-2

still writing the zeros to all relevant files to keep them compatible (file formats do NOT
change, only the values)
adapting fluid strain to u_phi = 0

+ some tidying up of stuff not used anymore
in case of dipole, transform to s/phi before dumping displacements

incrementing file version number of the netcdf file, as this requires changes to the
kerner
updating welcome message
bugfix in wavefield output
fixing fluid stiffness