Add trace crack result

StructureHelperLogics/NdmCalculations/Cracking/ICrackCalculator.cs

@@ -2,8 +2,14 @@
 
 namespace StructureHelperLogics.NdmCalculations.Cracking
 {
+    /// <summary>
+    /// Calculates width of cracks for cross-section by collection of combination of forces
+    /// </summary>
     public interface ICrackCalculator : ICalculator
     {
+        /// <summary>
+        /// Input data for crack calculations
+        /// </summary>
         ICrackCalculatorInputData InputData { get; set; }
     }
 }