Visual Studio 2017 MSBuild Task Development

With developing an custom MSBuild Task with Visual Studio 2017 RC, I have the following problem: As soon as I add other dependencies than just Microsoft.Build.Utilities.Core (using v15.1.0-preview-000458-02 for .NET Core Support), I cannot load the task into another .csproj MSBuild project as the dependencies are not found.

Is there a way to automatically copy all dependencies to the Debug folder? Or do I have to publish it every time I want to test it?

Update1:
The problem with publish was something local to my environment and has been fixed.

Update2:
It seems that as soon as I change the TargetFramework from netstandard1.4 to netstandard1.6 it isn't even able to load the task at all. As soon as I use netstandard 1.6 it throws a an exception:

The task could not be loaded from the assembly.
Could not load file or assembly 'System.Runtime, Version=4.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
dependencies.

Is there a way to automatically copy all dependencies to the Debug folder? Or do I have to publish it every time I want to test it?

By default and for good reasons, .NET Core and .NET Standard projects do not copy referenced assemblies into the build folder. Instead, they are resolved them from the NuGet cache.

But if you really need it, this behavior can be changed by overriding the default with the CopyLocalLockFileAssemblies setting.

<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>

Cref: https://github.com/dotnet/sdk/blob/d20405f91a2959fa91fea6285d9a896286727f2a/src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.Sdk.BeforeCommon.targets#L55-L56

Second question

It seems that as soon as I change the TargetFramework from netstandard1.4 to netstandard1.6

To build a task assembly that works on both "MSBuild.exe" and "dotnet.exe msbuild", you should target netstandard1.4 or lower. netstandard1.6 is not compatible with .NET Framework 4.6.1 (which MSBuild.exe runs on.)

If you need API not available in netstandard1.4, you will need to cross-compile your task for .NET Framework and .NET Standard, which is considerably more complex but can be done.