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/Cli/Dynamic/Dynamic.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <IsPackable>false</IsPackable>
+    <ExampleName>Dynamic</ExampleName>
+    <ExampleDescription>Demonstrates how to define dynamic commands.</ExampleDescription>
+    <ExampleGroup>Cli</ExampleGroup>
+    <ExampleVisible>false</ExampleVisible>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\Spectre.Console\Spectre.Console.csproj" />
+  </ItemGroup>
+
+</Project>

examples/Cli/Dynamic/MyCommand.cs

@@ -0,0 +1,20 @@
+using System;
+using Spectre.Console.Cli;
+
+namespace Dynamic
+{
+    public sealed class MyCommand : Command
+    {
+        public override int Execute(CommandContext context)
+        {
+            if (!(context.Data is int data))
+            {
+                throw new InvalidOperationException("Command has no associated data.");
+                
+            }
+
+            Console.WriteLine("Value = {0}", data);
+            return 0;
+        }
+    }
+}

examples/Cli/Dynamic/Program.cs

@@ -0,0 +1,24 @@
+using System.Linq;
+using Spectre.Console.Cli;
+
+namespace Dynamic
+{
+    public static class Program
+    {
+        public static int Main(string[] args)
+        {
+            var app = new CommandApp();
+            app.Configure(config =>
+            {
+                foreach(var index in Enumerable.Range(1, 10))
+                {
+                    config.AddCommand<MyCommand>($"c{index}")
+                        .WithDescription($"Prints the number {index}")
+                        .WithData(index);
+                }
+            });
+
+            return app.Run(args);
+        }
+    }
+}