Convert C# projects to MSBuild (csproj) format

This has one important packaging change: the netstandard version now
depends (implicitly) on netstandard1.6.1 rather than on individual
packages. This is the preferred style of dependency, and shouldn't
affect any users - see http://stackoverflow.com/questions/42946951
for details.

The tests are still NUnit, but NUnit doesn't support "dotnet test"
yet; the test project is now an executable using NUnitLite. (When
NUnit supports dotnet test, we can adapt to it.)

Note that the project will now only work in Visual Studio 2017 (and
Visual Studio Code, and from the command line with the .NET Core
1.0.0 SDK); Visual Studio 2015 does *not* support this project file
format.

3 files changed, 14 insertions, 40 deletions

diff --git a/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.csproj b/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.csproj
new file mode 100644
index 00000000..b654c0b2
--- /dev/null
+++ b/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp1.0</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <IsPackable>False</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Google.Protobuf\Google.Protobuf.csproj" />
+    <ProjectReference Include="..\Google.Protobuf.Test\Google.Protobuf.Test.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.xproj b/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.xproj
deleted file mode 100644
index 99ff1465..00000000
--- a/csharp/src/Google.Protobuf.Conformance/Google.Protobuf.Conformance.xproj
+++ /dev/null
@@ -1,19 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <PropertyGroup>
-    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
-    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
-  </PropertyGroup>
-  <Import Project="$(VSToolsPath)\DotNet\Microsoft.DotNet.Props" Condition="'$(VSToolsPath)' != ''" />
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>dddc055b-e185-4181-bab0-072f0f984569</ProjectGuid>
-    <RootNamespace>Google.Protobuf.Conformance</RootNamespace>
-    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">.\obj</BaseIntermediateOutputPath>
-    <OutputPath Condition="'$(OutputPath)'=='' ">.\bin\</OutputPath>
-  </PropertyGroup>
-
-  <PropertyGroup>
-    <SchemaVersion>2.0</SchemaVersion>
-  </PropertyGroup>
-  <Import Project="$(VSToolsPath)\DotNet\Microsoft.DotNet.targets" Condition="'$(VSToolsPath)' != ''" />
-</Project>
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf.Conformance/project.json b/csharp/src/Google.Protobuf.Conformance/project.json
deleted file mode 100644
index 4cf05231..00000000
--- a/csharp/src/Google.Protobuf.Conformance/project.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "buildOptions": {
-    "debugType": "portable",
-    "emitEntryPoint": true
-  },
-  "dependencies": {
-    "Google.Protobuf": { "target": "project" },
-    "Google.Protobuf.Test": { "target": "project" }
-  },
-  "frameworks": {
-    "netcoreapp1.0": {
-      "imports": [ "dnxcore50", "netcoreapp1.0", "portable-net45+win8" ],
-      "dependencies": {
-        "Microsoft.NETCore.App": {
-          "type": "platform",
-          "version": "1.0.0"
-        }
-      }
-    }
-  }
-}