tvOS sample: update libvlc

Samples/LibVLCSharp.tvOS.Sample/LibVLCSharp.tvOS.Sample.csproj

-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -9,6 +9,8 @@
     <RootNamespace>LibVLCSharp.tvOS.Sample</RootNamespace>
     <AssemblyName>LibVLCSharp.tvOS.Sample</AssemblyName>
     <IPhoneResourcePrefix>Resources</IPhoneResourcePrefix>
+    <NuGetPackageImportStamp>
+    </NuGetPackageImportStamp>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|iPhoneSimulator' ">
     <DebugSymbols>true</DebugSymbols>
@@ -175,5 +177,11 @@
     </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\TVOS\Xamarin.TVOS.CSharp.targets" />
-  <Import Project="..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha\build\VideoLAN.LibVLC.tvOS.targets" Condition="Exists('..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha\build\VideoLAN.LibVLC.tvOS.targets')" />
+  <Import Project="..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha1\build\VideoLAN.LibVLC.tvOS.targets" Condition="Exists('..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha1\build\VideoLAN.LibVLC.tvOS.targets')" />
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha1\build\VideoLAN.LibVLC.tvOS.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\VideoLAN.LibVLC.tvOS.3.2.0-alpha1\build\VideoLAN.LibVLC.tvOS.targets'))" />
+  </Target>
 </Project>
\ No newline at end of file

Samples/LibVLCSharp.tvOS.Sample/packages.config

 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="VideoLAN.LibVLC.tvOS" version="3.2.0-alpha" targetFramework="xamarintvos10" />
+  <package id="VideoLAN.LibVLC.tvOS" version="3.2.0-alpha1" targetFramework="xamarintvos10" />
 </packages>
\ No newline at end of file