… .NETStandard2.0

…project file. When reverted back to internal on functions/classes

…References.cs.

Removed dependencies for Mono.Addins.MSBuild on Mono.Addins.Setup. Not needed

MultiAssemblyAddin project has two projects in its directory
and the SDK style file globs were including .cs files from
these projects causing compilation errors. These project
directories are now excluded from the project.

The path was being created without the path separator for the
Mono.Addins.SetupProcess assembly. Also the file extension was
incorrectly set to .dll when running with Mono.

The project was hard coded to target .NET 4.7.2 instead of using
the TargetFramework.props file. This was preventing it being
referenced by the UnitTests project.

The tests do not run tests with the external SetupProcess currently
but having the UnitTests copy this allows this to be tested locally
by changing the AddinDatabase.GetSetupHandler method.

Fixed the setup process tool trying to use too many command line
arguments. The out directory is passed on stdin not as a command
line argument.

Still have warnings about conflicts in mautil.
One warning about Mono.Addins not being strong named.

Test addins now built into the lib directory instead of a subdirectory
based on the target framework.

UnitTests project now built without appending its target framework
to the build directory.

This fixes some tests that were relying on the location of the
test addins being in the lib directory. Still 38 tests failing.

Some tests were checking the assembly version of the test addins
were 0.0.0.0 however the default for SDK style projects seems to be
1.0.0.0. Changed the test addin projects to use the 0.0.0.0 version.

With the non-SDK style projects the DEBUG symbol is not defined
so the Debug.Assert is not called. The Debug.Assert looks wrong.
It is asserting that the dictionary contains the RuntimeAddin but
that is always false when initially loading the dictionary. Commented
this line out.

It was targeting the .NET Framework.

Set AppendTargetFrameworkToOutputPath to false in all projects
so everything builds into the same bin directory.

Fix warnings about assemblies not being strong named.
The internals visible to information was missing the
public key.

Before the UnitTests was using a ProjectReference without
ReferenceOutputAssembly set to false. This would prevent
the project building if the SetupProcess project was
targeting an incompatible target framework, such as .NET
Core. Now ReferenceOutputAssembly is set to false on the
project reference and the executable files are copied in
a custom msbuild target after the build finishes. Also
have to add SkipGetTargetFrameworkProperties to true
for the project reference to workaround an MSBuild bug
where the build fails with UnitTests referencing a
.NET Core 3.1 SetupProcess project even though it does
not compile against its assemblies.

The original logic tried to run the dll directly which did
not work. Now a check is made to see if the .exe is
available and that is run if it is available. Then a check
is made to see if there is a native build of the exe
available. Finally the code falls back to running the dll
with dotnet.

Those can't be built on .net standard. Leave them
targetting 4.7 for now