Add support for recording console output

This commit adds support for recording console output
as well as exporting it to either text or HTML. A user can
also provide their own encoder if they wish.

src/Spectre.Console/Extensions/AnsiConsoleExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using Spectre.Console.Rendering;
 
 namespace Spectre.Console
 {
@@ -7,6 +8,32 @@ namespace Spectre.Console
     /// </summary>
     public static partial class AnsiConsoleExtensions
     {
+        /// <summary>
+        /// Creates a recorder for the specified console.
+        /// </summary>
+        /// <param name="console">The console to record.</param>
+        /// <returns>A recorder for the specified console.</returns>
+        public static Recorder CreateRecorder(this IAnsiConsole console)
+        {
+            return new Recorder(console);
+        }
+
+        /// <summary>
+        /// Writes the specified string value to the console.
+        /// </summary>
+        /// <param name="console">The console to write to.</param>
+        /// <param name="text">The text to write.</param>
+        /// <param name="style">The text style.</param>
+        public static void Write(this IAnsiConsole console, string text, Style style)
+        {
+            if (console is null)
+            {
+                throw new ArgumentNullException(nameof(console));
+            }
+
+            console.Write(new Segment(text, style));
+        }
+
         /// <summary>
         /// Writes an empty line to the console.
         /// </summary>
@@ -34,7 +61,7 @@ namespace Spectre.Console
                 throw new ArgumentNullException(nameof(console));
             }
 
-            console.Write(text, style);
+            console.Write(new Segment(text, style));
             console.WriteLine();
         }
     }

src/Spectre.Console/Extensions/RecorderExtensions.cs

@@ -0,0 +1,44 @@
+using System;
+using Spectre.Console.Internal;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Contains extension methods for <see cref="Recorder"/>.
+    /// </summary>
+    public static class RecorderExtensions
+    {
+        private static readonly TextEncoder _textEncoder = new TextEncoder();
+        private static readonly HtmlEncoder _htmlEncoder = new HtmlEncoder();
+
+        /// <summary>
+        /// Exports the recorded content as text.
+        /// </summary>
+        /// <param name="recorder">The recorder.</param>
+        /// <returns>The recorded content as text.</returns>
+        public static string ExportText(this Recorder recorder)
+        {
+            if (recorder is null)
+            {
+                throw new ArgumentNullException(nameof(recorder));
+            }
+
+            return recorder.Export(_textEncoder);
+        }
+
+        /// <summary>
+        /// Exports the recorded content as HTML.
+        /// </summary>
+        /// <param name="recorder">The recorder.</param>
+        /// <returns>The recorded content as HTML.</returns>
+        public static string ExportHtml(this Recorder recorder)
+        {
+            if (recorder is null)
+            {
+                throw new ArgumentNullException(nameof(recorder));
+            }
+
+            return recorder.Export(_htmlEncoder);
+        }
+    }
+}