Improve consistency for SWCR

[alifbe]

There are two issues that potentially create inconsistency Swcr (critical saturation)

1. Precision of relative permeability generated by pyscal. In this example, pyscal reported Swcr = 0.057 but from the table we see that it should be 0.064 since it's the largest Sw where krw is zero. (It is zero due to precision of pyscal output)
2. From this table, Eclipse will pick 0.084 as Swcr since its criterion for zero is less than a threshold value which by default is 1.0E-6 (E100/Flow) and 1.0E-20 (E300)

SWOF
-- SCAL recommendation interpolation to 0.5
-- SATNUM 1 
-- pyscal: v0.12
-- swirr=0 swl=0.044 swcr=0.057 sorw=0.239814
-- krw = krow @ sw=0.56776
-- SW     KRW       KROW      PC        
0.0440000 0.0000000 1.0000000 10.8329040
0.0540000 0.0000000 0.9893945 6.8304541
0.0570000 0.0000000 0.9854823 6.0474202
0.0640000 0.0000000 0.9752507 4.6588961
0.0740000 0.0000002 0.9588309 3.3596226
0.0840000 0.0000008 0.9406121 2.5253604
0.0940000 0.0000021 0.9207817 1.9602723
0.1040000 0.0000043 0.8994980 1.5611378