Add Proguard config support

Author: dellis1972

OpenTK.props

@@ -1,5 +1,5 @@
 <Project>
     <PropertyGroup>
-        <_OpenTKNugetVersion>0.0.1-alpha</_OpenTKNugetVersion>
+        <_OpenTKNugetVersion>1.0.0</_OpenTKNugetVersion>
     </PropertyGroup>
 </Project>

Projects/OpenTK.Android/OpenTK.Android.csproj

@@ -74,5 +74,10 @@
         <PackageOutputPath>$(MSBuildThisFileDirectory)..\..\</PackageOutputPath>
         <AllowedOutputExtensionsInPackageBuildOutputFolder>.pdb;$(AllowedOutputExtensionsInPackageBuildOutputFolder)</AllowedOutputExtensionsInPackageBuildOutputFolder>
     </PropertyGroup>
+
+    <ItemGroup>
+        <None Include="Xamarin.Legacy.OpenTK.targets" PackagePath="build" Pack="true" />
+        <None Include="OpenTK.cfg" PackagePath="build" Pack="true" />
+    </ItemGroup>
 
 </Project>

Projects/OpenTK.Android/OpenTK.cfg

@@ -0,0 +1,4 @@
+-keep class opentk.platform.android.AndroidGameView { *; <init>(...); }
+-keep class opentk.GameViewBase { *; <init>(...); }
+-keep class opentk_1_0.platform.android.AndroidGameView { *; <init>(...); }
+-keep class opentk_1_0.GameViewBase { *; <init>(...); }

Projects/OpenTK.Android/Xamarin.Legacy.OpenTK.targets

@@ -0,0 +1,5 @@
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+    <ItemGroup>
+        <ProguardConfiguration Include="$(MSBuildThisFileDirectory)OpenTK.cfg" />
+    </ItemGroup>
+</Project>