Add Spectre.Cli to Spectre.Console

* Renames Spectre.Cli to Spectre.Console.Cli.
* Now uses Verify with Spectre.Console.Cli tests.
* Removes some duplicate definitions.

Closes #168

examples/Console/Progress/Program.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using Spectre.Console;
+
+namespace ProgressExample
+{
+    public static class Program
+    {
+        public static void Main()
+        {
+            AnsiConsole.MarkupLine("[yellow]Initializing warp drive[/]...");
+
+            // Show progress
+            AnsiConsole.Progress()
+                .AutoClear(false)
+                .Columns(new ProgressColumn[]
+                {
+                    new TaskDescriptionColumn(),    // Task description
+                    new ProgressBarColumn(),        // Progress bar
+                    new PercentageColumn(),         // Percentage
+                    new RemainingTimeColumn(),      // Remaining time
+                    new SpinnerColumn(),            // Spinner
+                })
+                .Start(ctx =>
+                {
+                    var random = new Random(DateTime.Now.Millisecond);
+                    var tasks = CreateTasks(ctx, random);
+
+                    while (!ctx.IsFinished)
+                    {
+                        // Increment progress
+                        foreach (var (task, increment) in tasks)
+                        {
+                            task.Increment(random.NextDouble() * increment);
+                        }
+
+                        // Write some random things to the terminal
+                        if (random.NextDouble() < 0.1)
+                        {
+                            WriteLogMessage();
+                        }
+
+                        // Simulate some delay
+                        Thread.Sleep(100);
+                    }
+                });
+
+            // Done
+            AnsiConsole.MarkupLine("[green]Done![/]");
+        }
+
+        private static List<(ProgressTask, int)> CreateTasks(ProgressContext progress, Random random)
+        {
+            var tasks = new List<(ProgressTask, int)>();
+            while (tasks.Count < 5)
+            {
+                if (DescriptionGenerator.TryGenerate(out var name))
+                {
+                    tasks.Add((progress.AddTask(name), random.Next(2, 10)));
+                }
+            }
+
+            return tasks;
+        }
+
+        private static void WriteLogMessage()
+        {
+            AnsiConsole.MarkupLine(
+                "[grey]LOG:[/] " +
+                DescriptionGenerator.Generate() +
+                "[grey]...[/]");
+        }
+    }
+}