Removed nuget libraries for Android and iOS targets

They are part of Xamarin bcl.

build/Android.props

@@ -1,18 +0,0 @@
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup>
-    <PackageReference Include="System.Collections" Version="4.3.0" />
-    <PackageReference Include="System.Collections.Concurrent" Version="4.3.0" />
-    <PackageReference Include="System.ComponentModel" Version="4.3.0" />
-    <PackageReference Include="System.Diagnostics.Debug" Version="4.3.0" />
-    <PackageReference Include="System.Diagnostics.Tools" Version="4.3.0" />
-    <PackageReference Include="System.Globalization" Version="4.3.0" />
-    <PackageReference Include="System.Linq" Version="4.3.0" />
-    <PackageReference Include="System.Reflection" Version="4.3.0" />
-    <PackageReference Include="System.Resources.ResourceManager" Version="4.3.0" />
-    <PackageReference Include="System.Runtime" Version="4.3.0" />
-    <PackageReference Include="System.Runtime.Extensions" Version="4.3.0" />
-    <PackageReference Include="System.Text.RegularExpressions" Version="4.3.0" />
-    <PackageReference Include="System.Threading" Version="4.3.0" />
-    <PackageReference Include="System.Threading.Tasks" Version="4.3.0" />
-  </ItemGroup>
-</Project>

build/iOS.props

@@ -1,18 +0,0 @@
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup>
-    <PackageReference Include="System.Collections" Version="4.3.0" />
-    <PackageReference Include="System.Collections.Concurrent" Version="4.3.0" />
-    <PackageReference Include="System.ComponentModel" Version="4.3.0" />
-    <PackageReference Include="System.Diagnostics.Debug" Version="4.3.0" />
-    <PackageReference Include="System.Diagnostics.Tools" Version="4.3.0" />
-    <PackageReference Include="System.Globalization" Version="4.3.0" />
-    <PackageReference Include="System.Linq" Version="4.3.0" />
-    <PackageReference Include="System.Reflection" Version="4.3.0" />
-    <PackageReference Include="System.Resources.ResourceManager" Version="4.3.0" />
-    <PackageReference Include="System.Runtime" Version="4.3.0" />
-    <PackageReference Include="System.Runtime.Extensions" Version="4.3.0" />
-    <PackageReference Include="System.Runtime.InteropServices.WindowsRuntime" Version="4.3.0" />
-    <PackageReference Include="System.Threading" Version="4.3.0" />
-    <PackageReference Include="System.Threading.Tasks" Version="4.3.0" />
-  </ItemGroup>
-</Project>

build/readme.md

@@ -1,8 +1,6 @@
 ### MSBuild Props
 
 ```XML
-<Import Project="..\..\build\Android.props" />
-<Import Project="..\..\build\iOS.props" />
 <Import Project="..\..\build\JetBrains.Annotations.props" />
 <Import Project="..\..\build\JetBrains.dotMemoryUnit.props" />
 <Import Project="..\..\build\Magick.NET-Q16-AnyCPU.props" />

src/Android/Avalonia.Android/Avalonia.Android.csproj

@@ -132,7 +132,6 @@
   <ItemGroup />
   <Import Project="..\..\Shared\PlatformSupport\PlatformSupport.projitems" Label="Shared" />
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
-  <Import Project="..\..\..\build\Android.props" />
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="$(MSBuildThisFileDirectory)..\..\Shared\nuget.workaround.targets" />
   <PropertyGroup Condition="'$(UseRoslynPathHack)' == ''">

src/Android/Avalonia.AndroidTestApplication/Avalonia.AndroidTestApplication.csproj

@@ -153,7 +153,6 @@
     </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
-  <Import Project="..\..\..\build\Android.props" />
   <Import Project="..\..\..\build\Serilog.props" />
   <Import Project="..\..\..\build\Splat.props" />
   <Import Project="..\..\..\build\Sprache.props" />

src/iOS/Avalonia.iOS/Avalonia.iOS.csproj

@@ -104,7 +104,6 @@
   </ItemGroup>
   <Import Project="..\..\Shared\PlatformSupport\PlatformSupport.projitems" Label="Shared" />
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\iOS\Xamarin.iOS.CSharp.targets" />
-  <Import Project="..\..\..\build\iOS.props" />
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="$(MSBuildThisFileDirectory)..\..\Shared\nuget.workaround.targets" />
 </Project>

src/iOS/Avalonia.iOSTestApplication/Avalonia.iOSTestApplication.csproj

@@ -186,7 +186,6 @@
     </EmbeddedResource>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\iOS\Xamarin.iOS.CSharp.targets" />
-  <Import Project="..\..\..\build\iOS.props" />
   <Import Project="..\..\..\build\Rx.props" />
   <Import Project="$(MSBuildThisFileDirectory)..\..\Shared\nuget.workaround.targets" />
 </Project>