cell-to-cell connections (i.e., when calling count_block_conns()),
inspect the pointer array (pc2c) rather than the cell array itself
(c2c). Clue-by-four supplied by gdb(1).
Move self connection handling to partition_create_c2c().
Adjust dfs() 'work' array size to comply with new requirements of
-r5088.
implements the first edition of the 'partitionUI' algorithm (i.e.,
before afg added sub-grid support in r2349), but it is nevertheless
a useful experiment and facilitates testing a C/C++ implementation
of the MsMFE method.