[cg_level] s/mpi_bnd_types/find_neighbors/, slightly updated descriptions
[cg_level] Added flag that will be useful for looking for neighbours in SFC-way
copied src/grid/sort_piece_list.F90 to src/base/sortable_list.F90
sorting routine moved to an abstract type
[cg_level] sketched find_neighbors_SFC, a faster replacement for find_neighbors_bruteforce
[cg_level] calculate potential neighbours id in find_neighbors_SFC
made some types abstract to suggest that these are not for direct use
cosmetics
[cg_level_coarsest] removed duplicated code
[cg_level] made cg_level_T%patches private
comment
started movving cg_level_T%patches to a separate type
moved cg_level_T%expand_list to patch_list_T%expand
moved cg_level_T%count_patches to patch_list_T%p_count
moved some code from cg_level to patch_list
[cg_level] cosmetics
Merge branch 'separate_patches_type' into SFC_neighbors
[patch_list] cosmetics
New module to take out some load-balance related code from cg_level
moved cg_level_T%balance_new to a new abstract type