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/IConfigurator.cs

@@ -0,0 +1,49 @@
+using System;
+
+namespace Spectre.Console.Cli
+{
+    /// <summary>
+    /// Represents a configurator.
+    /// </summary>
+    public interface IConfigurator
+    {
+        /// <summary>
+        /// Gets the command app settings.
+        /// </summary>
+        public ICommandAppSettings Settings { get; }
+
+        /// <summary>
+        /// Adds an example of how to use the application.
+        /// </summary>
+        /// <param name="args">The example arguments.</param>
+        void AddExample(string[] args);
+
+        /// <summary>
+        /// Adds a command.
+        /// </summary>
+        /// <typeparam name="TCommand">The command type.</typeparam>
+        /// <param name="name">The name of the command.</param>
+        /// <returns>A command configurator that can be used to configure the command further.</returns>
+        ICommandConfigurator AddCommand<TCommand>(string name)
+            where TCommand : class, ICommand;
+
+        /// <summary>
+        /// Adds a command that executes a delegate.
+        /// </summary>
+        /// <typeparam name="TSettings">The command setting type.</typeparam>
+        /// <param name="name">The name of the command.</param>
+        /// <param name="func">The delegate to execute as part of command execution.</param>
+        /// <returns>A command configurator that can be used to configure the command further.</returns>
+        ICommandConfigurator AddDelegate<TSettings>(string name, Func<CommandContext, TSettings, int> func)
+            where TSettings : CommandSettings;
+
+        /// <summary>
+        /// Adds a command branch.
+        /// </summary>
+        /// <typeparam name="TSettings">The command setting type.</typeparam>
+        /// <param name="name">The name of the command branch.</param>
+        /// <param name="action">The command branch configurator.</param>
+        void AddBranch<TSettings>(string name, Action<IConfigurator<TSettings>> action)
+            where TSettings : CommandSettings;
+    }
+}