Fix Wox restart

1. refactoring restart
2. delte some windows forms methods
3. using string inteperlation and delete hard coeded new line char

should fix #322

Wox.Plugin/IPublicAPI.cs

@@ -51,6 +51,11 @@ namespace Wox.Plugin
         /// </summary>
         void CloseApp();
 
+        /// <summary>
+        /// Restart Wox
+        /// </summary>
+        void RestarApp();
+
         /// <summary>
         /// Hide Wox
         /// </summary>