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/ClosedXML_Examples.csproj

@@ -0,0 +1,46 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.0;net40;net46</TargetFrameworks>
+    <LangVersion>8.0</LangVersion>
+    <OutputType>Exe</OutputType>
+    <Version>0.95.4</Version>
+    <NoWarn>$(NoWarn);NU1605</NoWarn>
+    <Configurations>Debug;Release;Release.Signed</Configurations>
+  </PropertyGroup>
+  
+  <PropertyGroup Condition="'$(Configuration)'=='Release.Signed'">
+    <OutputPath>bin\Release.Signed\</OutputPath>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
+    <DefineConstants>$(DefineConstants);STRONGNAME</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.0' ">
+    <DefineConstants>$(DefineConstants);_NETSTANDARD_;_NETSTANDARD2_0_</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" '$(TargetFramework)' == 'net40' ">
+    <DefineConstants>$(DefineConstants);_NETFRAMEWORK_;_NET40_</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" '$(TargetFramework)' == 'net46' ">
+    <DefineConstants>$(DefineConstants);_NETFRAMEWORK_;_NET46_</DefineConstants>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Include="Resources\*.jpg" />
+    <EmbeddedResource Include="Resources\*.png" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="..\.editorconfig" Link=".editorconfig" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ClosedXML\ClosedXML.csproj" />
+    <PackageReference Include="DocumentFormat.OpenXml" Version="2.7.2" />
+    <PackageReference Include="morelinq" Version="2.10.0" />
+  </ItemGroup>
+
+</Project>