BUGFIX: dot%update_SFC_id_range should be called after dot%update_global in case balence_old changed anything
Merge commit 'b23eb36' into SFC_neighbors
[dot] quit bisection in find_grid when some processes don't own anything (need better solution for massively parallel runs)
Merge commit 'f5efa7b' into SFC_neighbors
[cg_list_neighbors] neighours are searched using SFC whenever possible
[cg_list_neighbors] array of pointers to grid container separated from find_neighbors_bruteforce
[cg_list_neighbors] find_neighbors_SFC can now set appropriate pointers for local boundary exchanges
[dot] a comment on possible optimization
added a switch to force the code to refrain from using SFC neighbor searches in favour of bruteforce