Adds a README file to the NuGet package

Includes the README.md file in the generated NuGet package.
This allows users browsing the package to view the project's
README directly from the package details page.

Author: niemyjski

build/common.props

@@ -20,6 +20,7 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageOutputPath>$(SolutionDir)artifacts</PackageOutputPath>
     <PackageIcon>exceptionless-icon.png</PackageIcon>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <RepositoryUrl>$(PackageProjectUrl)</RepositoryUrl>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
@@ -40,6 +41,7 @@
 
   <ItemGroup>
     <None Include="../../build/exceptionless-icon.png" Pack="true" PackagePath="$(PackageIcon)" />
+    <None Include="../../README.md" Pack="true" PackagePath="$(PackageReadmeFile)" />
   </ItemGroup>
 
 </Project>