adjust_bathymetry() - read mask adjustments from file.

INTERFACE:

    subroutine adjust_bathymetry(fn)
    IMPLICIT NONE
DESCRIPTION:

Read bathymetry adjustments from file. INPUT PARAMETERS:

    character(len=*), intent(in)        :: fn
REVISION HISTORY:
LOCAL VARIABLES:
    integer                   :: unit = 25 ! kbk
    character(len=255)        :: line
    integer                   :: iostat
    integer                   :: i,j,k=0,n=-1
    integer                   :: il,jl,ih,jh
    REALTYPE                  :: x