#221 Plot the phase of the wavefunction

[Ulf Lorenz]

What and Why

This is a pretty nice feature of the Matlab version: Not only the magnitude of the density is plotted, but also the phase of the wavefunction. This makes is easier to spot, e.g., the nodes in an eigenstate or so.

Drawback: The concept of a phase makes no sense for densities, hence this would be a wavefunction-only feature, which puts more complexity on the plotting code.