Initial commit of the ClosedXML library

Establishes the foundational structure, core Excel functionality, and tooling.

- Implements base components for cells, ranges, columns, and rows.
- Integrates a custom calculation engine with a wide range of Excel functions.
- Adds comprehensive support for styling, conditional formatting, data validation, comments, pictures, and charts.
- Configures build setup, project metadata (NuGet), and developer guidelines.
- Includes editor and Git attributes for consistent code style and line endings.

ClosedXML_Examples/Misc/RightToLeft.cs

@@ -0,0 +1,21 @@
+using ClosedXML.Excel;
+using System;
+
+namespace ClosedXML_Examples.Misc
+{
+    public class RightToLeft : IXLExample
+    {
+        public void Create(String filePath)
+        {
+            var wb = new XLWorkbook();
+
+            var ws = wb.Worksheets.Add("RightToLeftSheet");
+            ws.Cell("A1").Value = "A1";
+            ws.Cell("B1").Value = "B1";
+            ws.Cell("C1").Value = "C1";
+            ws.RightToLeft = true;
+
+            wb.SaveAs(filePath);
+        }
+    }
+}