Finally, this is the implementation of issue 340: distributed cloudiness (through atmospheric loss factor and splitting coefficient). This mostly follows the lines of what has been recently implemented in MeteoIO with a few tricks to perform domain decomposition when running in parallel (either MPI or OpenMP).  as well as benefit from Snowpack's albedo feedback. In the first tests, when commenting out this albedo feedback and forcing horizontal components, it performs exactly the same as MeteoIO's implementation.

Since there is no meteo1d object anymore, Snowdrift had to be modified so it can extract what it needs from a vector of MeteoData. An hopefully better implementation of Snowdrift without slatation is also included.