Refactoring. Move system plugins to seperate DLLs.

Wox.Core/i18n/Language.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Wox.Core.i18n
+{
+    public class Language
+    {
+        public Language(string code, string display)
+        {
+            LanguageCode = code;
+            Display = display;
+        }
+
+        /// <summary>
+        /// E.g. En or Zh-CN
+        /// </summary>
+        public string LanguageCode { get; set; }
+
+        public string Display { get; set; }
+    }
+}