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.

1 files changed, 3 insertions, 16 deletions

diff --git a/tests.sh b/tests.sh
index 96550cb9..710389bc 100755
--- a/tests.sh
+++ b/tests.sh
@@ -93,30 +93,17 @@ build_csharp() {
   internal_build_cpp
   NUGET=/usr/local/bin/nuget.exe
 
-  if [ "$TRAVIS" == "true" ]; then
-    # Install latest version of Mono
-    sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-    sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1397BC53640DB551
-    echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list
-    sudo apt-get update -qq
-    sudo apt-get install -qq mono-devel referenceassemblies-pcl nunit
-
-    # Then install the dotnet SDK as per Ubuntu 14.04 instructions on dot.net.
-    sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
-    sudo apt-key adv --keyserver apt-mo.trafficmanager.net --recv-keys 417A0893
-    sudo apt-get update -qq
-    sudo apt-get install -qq dotnet-dev-1.0.0-preview2-003121
-  fi
-
   # Perform "dotnet new" once to get the setup preprocessing out of the
   # way. That spews a lot of output (including backspaces) into logs
   # otherwise, and can cause problems. It doesn't matter if this step
   # is performed multiple times; it's cheap after the first time anyway.
+  # (It also doesn't matter if it's unnecessary, which it will be on some
+  # systems. It's necessary on Jenkins in order to avoid unprintable
+  # characters appearing in the JUnit output.)
   mkdir dotnettmp
   (cd dotnettmp; dotnet new > /dev/null)
   rm -rf dotnettmp
 
-  (cd csharp/src; dotnet restore)
   csharp/buildall.sh
   cd conformance && make test_csharp && cd ..