Refactoring pinyin

1. use custom patched pinyin library Pinyin4Net
2. fix memory leak on startup: 360mb -> 160mb when using vs15 debugger

Wox.Infrastructure/Alphabet.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using hyjiacan.util.p4n;
+
+namespace Wox.Infrastructure
+{
+    public static class Alphabet
+    {
+        /// <summary>
+        /// replace chinese character with pinyin, non chinese character won't be modified
+        /// <param name="word"> should be word or sentence, instead of single character. e.g. 微软 </param>
+        /// </summary>
+        public static string[] Pinyin(string word)
+        {
+            var pinyin = word.Select(c =>
+                             {
+                                 var pinyins = PinyinHelper.toHanyuPinyinStringArray(c);
+                                 var result = pinyins == null ? c.ToString() : pinyins[0];
+                                 return result;
+                             }).ToArray();
+            return pinyin;
+        }
+
+        /// <summmary>
+        /// replace chinese character with pinyin, non chinese character won't be modified
+        /// Because we don't have words dictionary, so we can only return all possiblie pinyin combination
+        /// e.g. 音乐 will return yinyue and yinle
+        /// <param name="word"> should be word or sentence, instead of single character. e.g. 微软 </param>
+        /// </summmary>
+        public static string[][] PinyinComination(string word)
+        {
+            var combination = word.Select(c =>
+                                   {
+                                       var pinyins = PinyinHelper.toHanyuPinyinStringArray(c);
+                                       var result = pinyins ?? new[] { c.ToString() };
+                                       return result;
+                                   }).Aggregate(Combination)
+                                   .Select(c => c.Split(';'))
+                                   .ToArray();
+            return combination;
+        }
+
+        public static string Acronym(string[] pinyin)
+        {
+            var acronym = string.Join("", pinyin.Select(p => p[0]));
+            return acronym;
+        }
+
+        public static bool ContainsChinese(string word)
+        {
+            var chinese = word.Select(PinyinHelper.toHanyuPinyinStringArray)
+                              .Any(p => p != null);
+            return chinese;
+        }
+
+        private static string[] Combination(string[] array1, string[] array2)
+        {
+            var combination = (
+                from a1 in array1
+                from a2 in array2
+                select $"{a1};{a2}"
+            ).ToArray();
+            return combination;
+        }
+    }
+}