Add logic for import of combination from xls files

StructureHelperCommon/Models/Forces/IColumnedFileProperty.cs

@@ -0,0 +1,33 @@
+using StructureHelperCommon.Infrastructures.Enums;
+using StructureHelperCommon.Infrastructures.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Models.Forces
+{
+    /// <summary>
+    /// Settings for extracting force combination from MSExcel file
+    /// </summary>
+    public interface IColumnedFileProperty : IFileProperty
+    {
+        /// <summary>
+        /// Count of rows before header
+        /// </summary>
+        int SkipRowBeforeHeaderCount { get; set; }
+        /// <summary>
+        /// Count of rows of header
+        /// </summary>
+        int SkipRowHeaderCount { get; set; }
+        /// <summary>
+        /// Factor which imported value multyply to
+        /// </summary>
+        double GlobalFactor { get; set; }
+        /// <summary>
+        /// Collection of column's properties which will be imported
+        /// </summary>
+        List<IColumnProperty> ColumnProperties { get; }
+    }
+}