Slightly optimizing error and errorNULL macro
- remove global variables
- greatly simplify path2filename
- permsRekursiv reworked to take pointer, as most callers use pointers
- changed readdir routine in add_deep to handle DT_UNKNOWN and d->d_type missing
- recreated varray_del, as the old had problems with read-pointer updates
- changed last_block_pos and read_block_pos to unsigned size_t, mainly to detect wrong assignment