Rename existing vector drawable targets to

The new generated targets file will take over the old name.  The old task goes into its own targets file with its own new name.

Author: Redth

vector-drawable/buildtask/Vector-Drawable-BuildTasks.csproj

@@ -40,7 +40,7 @@
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
-    <None Include="Xamarin.Android.Support.Vector.Drawable.targets">
+    <None Include="Xamarin.Android.Support.Tasks.VectorDrawable.targets">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </None>
   </ItemGroup>