Revision 137

Removed unused argument missval in ma_fucoll_r[1-3]1, ma_fufill_r[1-3]1.

Split filtreg into two procedures: filtreg_scal and filtreg_v. I did
not like the test on the extent of the argument and there was no
common code between the two cases: jjm and jjm + 1. Also, it is
simpler now to just remove the argument "direct" from filtreg_v instead
of allowing it and then stopping the program if it is false.

Removed the computation of pkf in reanalyse2nat, was not used.

As a consequence of the split of filtreg, had to extract the
computation of pkf out of exner_hyb. This is clearer anyway because we
want to be able to call exner_hyb with any size in the first two
dimensions (as in test_disvert). But at the same time exner_hyb
required particular sizes for the computation of pkf. It was
awkward. The only computation of pkf is now in leapfrog.