Extract all converters into separate folder

Wox/Converters/ConvertorBase.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+using System.Windows.Markup;
+
+namespace Wox.Converters
+{
+    public abstract class ConvertorBase<T> : MarkupExtension, IValueConverter where T : class, new()
+    {
+        private static T converter;
+
+        /// <summary>
+        /// Must be implemented in inheritor.
+        /// </summary>
+        public abstract object Convert(object value, Type targetType, object parameter, CultureInfo culture);
+
+        /// <summary>
+        /// Override if needed.
+        /// </summary>
+        public virtual object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override object ProvideValue(IServiceProvider serviceProvider)
+        {
+            return converter ?? (converter = new T());
+        }
+    }
+}