Add NUnit3 Test Adapter to run NUnit tests from VS

Author: Vogel612

RubberduckTests/RubberduckTests.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\packages\NUnit3TestAdapter.3.9.0\build\net35\NUnit3TestAdapter.props" Condition="Exists('..\packages\NUnit3TestAdapter.3.9.0\build\net35\NUnit3TestAdapter.props')" />
   <Import Project="..\packages\LibGit2Sharp.NativeBinaries.1.0.185\build\LibGit2Sharp.NativeBinaries.props" Condition="Exists('..\packages\LibGit2Sharp.NativeBinaries.1.0.185\build\LibGit2Sharp.NativeBinaries.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -489,6 +490,7 @@
     </PropertyGroup>
     <Error Condition="!Exists('$(SolutionDir)\.nuget\NuGet.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\.nuget\NuGet.targets'))" />
     <Error Condition="!Exists('..\packages\LibGit2Sharp.NativeBinaries.1.0.185\build\LibGit2Sharp.NativeBinaries.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\LibGit2Sharp.NativeBinaries.1.0.185\build\LibGit2Sharp.NativeBinaries.props'))" />
+    <Error Condition="!Exists('..\packages\NUnit3TestAdapter.3.9.0\build\net35\NUnit3TestAdapter.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit3TestAdapter.3.9.0\build\net35\NUnit3TestAdapter.props'))" />
   </Target>
   <!-- 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.

RubberduckTests/packages.config

@@ -8,5 +8,6 @@
   <package id="NLog" version="4.4.12" targetFramework="net45" />
   <package id="NLog.Schema" version="4.4.12" targetFramework="net45" />
   <package id="NUnit" version="3.9.0" targetFramework="net45" />
+  <package id="NUnit3TestAdapter" version="3.9.0" targetFramework="net45" />
   <package id="System.ValueTuple" version="4.4.0" targetFramework="net45" />
 </packages>