Update the installer

Wox.Plugin/README.md

@@ -0,0 +1,5 @@
+What does Wox.Plugin do?
+====
+
+* Define base objects and interfaces for plugins
+* Plugin Author who making C# plugin should reference this DLL via nuget

Wox.Plugin/Wox.Plugin.csproj

@@ -59,6 +59,9 @@
     <Compile Include="Result.cs" />
     <Compile Include="ActionContext.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <None Include="README.md" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.