03-08-21 New Radiation option

Updated and improved calculation of outgoing longwave radiation in case of multiplecanopies and explicit account for the longwaveradiation based on surface temperature estimations. The canopy temperatures are distributed between individual canopies according to the varialbe MC_TempCanopy. The mean canopy temperature is still TempCanopy. The estimated output temperature variables are located in additional variable section of the model. The new version is more stable than the previous but we still do not recommend to use the explicit estimation of energy balance based on temperatures (See NetLongRad switch) if daily mean values are used as time resolution  DG