Changeset 7615 for trunk

Enhanced consistency of variable names: input has been changed in n_input throughout the code and the variable name vegstress introduced in sechiba is now also used in stomate. Enhnaced computational consistency: Pgap_cumul is used in stomate rather than recalculating it before calculating light_tran_to_floor_season. Edited getin_p while checking the code (but no real changes were made) and added several missing stomate and sechiba variables to age_class_distr to improve the 1+1=2 issue when comparing a model run with against a run without age classes. Finally: Write warning 10b in allocation to the history file rather than the out_orchidee file