Remove Avalonia.Dialogs dependency on diagnostics.

And add explicit dependency on `Avalonia.Diagnostics` to samples.

samples/BindingDemo/BindingDemo.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
   </ItemGroup>

samples/ControlCatalog/ControlCatalog.csproj

@@ -21,6 +21,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\packages\Avalonia\Avalonia.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.DataGrid\Avalonia.Controls.DataGrid.csproj" />
   </ItemGroup>

samples/RenderDemo/RenderDemo.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
   </ItemGroup>

samples/VirtualizationDemo/VirtualizationDemo.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.ReactiveUI\Avalonia.ReactiveUI.csproj" />
   </ItemGroup>

src/Avalonia.Dialogs/Avalonia.Dialogs.csproj

@@ -13,7 +13,6 @@
   <Import Project="..\..\build\BuildTargets.targets" />
 
   <ItemGroup>
-    <ProjectReference Include="..\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\Markup\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj" />
   </ItemGroup>
 </Project>