Needing a tutorial on time scale

[philippkraft]

Many hydrological models work with a fixed daily timestep, but processes like interception and surface runoff occur for a much shorter timestep. Every now and then CMF shows a "weird" behaviour, which is not weird at all, but just an artifact due to a too large timestep. We need a tutorial to help users select the "right" timestep in their solvers. And this means not too long.