Added missing CPP directives

[arango]

Corrected missing CPP directives in routines tl_step3d_uv.F and ad_step3d_uv.F. This bug was introduced in ​src:ticket:346. Many thanks to Gregoire Broquet and Andy Moore for reporting this.

I also corrected a small defect in tl_balance.F and ad_balance.F. We need to have:

      DO j=JstrR,JendR
        DO i=IstrR,IendR
          DO k=1,N(ng)
            cff=0.5_r8*(dTdz(i,j,k-1)+dTdz(i,j,k))
            IF (ABS(cff).lt.dTdz_min) THEN
              dzdT=0.0_r8
            ELSE
              dzdT=1.0_r8/cff
            END IF
            dSdT(k)=(0.5_r8*(dSdz(i,j,k-1)+                             &
     &                       dSdz(i,j,k  )))*dzdT
          END DO

instead of:

      DO j=JstrR,JendR
        DO i=IstrR,IendR
          DO k=1,N(ng)
            IF (ABS(dTdz(i,j,k)).lt.dTdz_min) THEN
              dzdT=0.0_r8
            ELSE
              dzdT=1.0_r8/(0.5_r8*(dTdz(i,j,k-1)+                       &
     &                             dTdz(i,j,k  )))
            END IF
            dSdT(k)=(0.5_r8*(dSdz(i,j,k-1)+                             &
     &                       dSdz(i,j,k  )))*dzdT
          END DO