[NuGet] Fix build errors after restoring MonoGame.Binaries package.

Fixed bug 23626 - Xamarin Studio doesn't recognize that files exist
after NuGet Update
https://bugzilla.xamarin.com/show_bug.cgi?id=23626

Restoring the MonoGame.Binaries NuGet package would not fix build
errors.

The MonoGame.Binaries NuGet package has a custom MSBuild .targets file
that adds extra references:

<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <ItemGroup>
    <Reference Include="MonoGame.Framework">
      <HintPath>$(MSBuildThisFileDirectory)\MonoGame.Framework.dll</HintPath>
    </Reference>
    <Reference Include="Tao.Sdl">
      <HintPath>$(MSBuildThisFileDirectory)\Tao.Sdl.dll</HintPath>
    </Reference>
    <Reference Include="OpenTK">
      <HintPath>$(MSBuildThisFileDirectory)\OpenTK.dll</HintPath>
    </Reference>
  </ItemGroup>
</Project>

If the MonoGame.Binaries NuGet package is not available on opening the
project in Xamarin Studio the project will fail to build after
restoring the NuGet package since the references are not refreshed.

Now after a NuGet package restore the RemoteProjectBuilder is
refreshed. This fixes the build errors however the text editor still
shows the types from the MonoGame.Binaries assemblies in red text
since the type system is unaware that they exist. So as well as
refreshing the RemoteProjectBuilder the TypeSystemService is asked
to reconnect the assembly references after packages have been
restored.
[NuGet] Refresh type system only when package has .targets/.props

When restoring the NuGet packages the NuGet addin would always refresh
the type system and the RemoteProjectBuilder. Now this refresh is only
done if one or more of the NuGet package being restored use a custom
MSBuild .targets or .props file.
Merge branch 'bug-23626-build-error-after-restoring-monogame-nuget-package'