Update SpiroNet.Editor.Wpf.csproj

[skip ci]

src/SpiroNet.Editor.Wpf/SpiroNet.Editor.Wpf.csproj

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -45,9 +45,7 @@
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="System.Net.Http" />
-    <Reference Include="System.Xaml">
-      <RequiredTargetFramework>4.0</RequiredTargetFramework>
-    </Reference>
+    <Reference Include="System.Xaml" />
     <Reference Include="WindowsBase" />
     <Reference Include="PresentationCore" />
     <Reference Include="PresentationFramework" />
@@ -107,11 +105,4 @@
     </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
-       Other similar extension points exist, see Microsoft.Common.targets.
-  <Target Name="BeforeBuild">
-  </Target>
-  <Target Name="AfterBuild">
-  </Target>
-  -->
-</Project>
+</Project>