[cg_level] comment on possible optimization of update_gse
cg_level_T%gse moved to a separate type
[dot] added cleanup routine
moved cg_level_T%update_gse to dot_T%update
moved piece of code from cg_level_T%create to dot_T%update_local
moved cg_level_T%update_tot_se to dot_T%update_tot_se
moved piece of code from cg_level_T%create to dot_T%is_consitent
cosmetics
[moved cg_level_T%is_blocky to dot_T together with some code to calculate it
moved stuff related to cg_level_T%SFC_id_range to dot_T