Cherry picked pinyin performance changes from jjw24's master branch

src/modules/launcher/Wox.Core/Resource/Internationalization.cs

@@ -99,6 +99,22 @@ namespace Wox.Core.Resource
 
         }
 
+        public bool PromptShouldUsePinyin(string languageCodeToSet)
+        {
+            var languageToSet = GetLanguageByLanguageCode(languageCodeToSet);
+
+            if (Settings.ShouldUsePinyin)
+                return false;
+
+            if (languageToSet != AvailableLanguages.Chinese && languageToSet != AvailableLanguages.Chinese_TW)
+                return false;
+
+            if (MessageBox.Show("Do you want to turn on search with Pinyin?", string.Empty, MessageBoxButton.YesNo) == MessageBoxResult.No)
+                return false;
+
+            return true;
+        }
+
         private void RemoveOldLanguageFiles()
         {
             var dicts = Application.Current.Resources.MergedDictionaries;

src/modules/launcher/Wox.Infrastructure/Alphabet.cs

@@ -162,7 +162,7 @@ namespace Wox.Infrastructure
 
             if (word.Length > 40)
             {
-                Log.Debug($"|Wox.Infrastructure.StringMatcher.ScoreForPinyin|skip too long string: {word}");
+                //Skip strings that are too long string for Pinyin conversion.
                 return false;
             }
 

src/modules/launcher/Wox.Infrastructure/UserSettings/Settings.cs

@@ -25,8 +25,7 @@ namespace Wox.Infrastructure.UserSettings
         /// <summary>
         /// when false Alphabet static service will always return empty results
         /// </summary>
-        public bool ShouldUsePinyin { get; set; } = true;
+        public bool ShouldUsePinyin { get; set; } = false;
-
 
         internal StringMatcher.SearchPrecisionScore QuerySearchPrecision { get; private set; } = StringMatcher.SearchPrecisionScore.Regular;
 

src/modules/launcher/Wox/ViewModel/SettingWindowViewModel.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -77,6 +77,33 @@ namespace Wox.ViewModel
             }
         }
 
+        public string Language
+        {
+            get
+            {
+                return Settings.Language;
+            }
+            set
+            {
+                InternationalizationManager.Instance.ChangeLanguage(value);
+
+                if (InternationalizationManager.Instance.PromptShouldUsePinyin(value))
+                    ShouldUsePinyin = true;
+            }
+        }
+
+        public bool ShouldUsePinyin
+        {
+            get 
+            {
+                return Settings.ShouldUsePinyin;            
+            }
+            set 
+            {
+                Settings.ShouldUsePinyin = value;
+            }
+        }
+
         public List<string> QuerySearchPrecisionStrings
         {
             get