To deal with different results in the computation of curvatures.
 FairCurve_OK describes the case where computation is successfully completed
 FairCurve_NotConverged describes the case where the algorithm does not converge. In this case, you can not be certain of the result quality and should resume computation if you want to make use of the curve.
 FairCurve_InfiniteSliding describes the case where sliding is infinite, and, consequently, computation stops. The solution is to use an imposed sliding value.
 FairCurve_NullHeight describes the case where no matter is left at one of the ends of the curve, and as a result, computation stops. The solution is to change (increase or reduce) the slope value by increasing or decreasing it.
Enumerator 

FairCurve_OK 

FairCurve_NotConverged 

FairCurve_InfiniteSliding 

FairCurve_NullHeight 
