Output of wavefunction coefficients broken with k-point parallelism

If we have `Diag.KProcGroups` set to give k-point parallelism then the output of wavefunction coefficients for pDOS and band-resolved densities does not work (some coefficients are not written out).

A simple, short-term fix would be to remove k-point parallelism if wavefunction coefficient output is set; it would be hard to enable output with k-point parallelism because of file access issues.