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

src/Spectre.Console/Cli/Internal/Commands/VersionCommand.cs

@@ -0,0 +1,34 @@
+using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Spectre.Console.Cli.Internal
+{
+    [Description("Displays the CLI library version")]
+    [SuppressMessage("Performance", "CA1812: Avoid uninstantiated internal classes")]
+    internal sealed class VersionCommand : Command<VersionCommand.Settings>
+    {
+        private readonly IAnsiConsole _writer;
+
+        public VersionCommand(IConfiguration configuration)
+        {
+            _writer = configuration.Settings.Console.GetConsole();
+        }
+
+        public sealed class Settings : CommandSettings
+        {
+        }
+
+        public override int Execute([NotNull] CommandContext context, [NotNull] Settings settings)
+        {
+            _writer.MarkupLine(
+                "[yellow]Spectre.Cli[/] version [aqua]{0}[/]",
+                VersionHelper.GetVersion(typeof(VersionCommand)?.Assembly));
+
+            _writer.MarkupLine(
+                "[yellow]Spectre.Console[/] version [aqua]{0}[/]",
+                VersionHelper.GetVersion(typeof(IAnsiConsole)?.Assembly));
+
+            return 0;
+        }
+    }
+}