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/Cursor/Program.cs

@@ -0,0 +1,20 @@
+using Spectre.Console;
+
+namespace Cursor
+{
+    public static class Program
+    {
+        public static void Main(string[] args)
+        {
+            AnsiConsole.Write("Hello");
+
+            // Move the cursor 3 cells to the right
+            AnsiConsole.Cursor.Move(CursorDirection.Right, 3);
+            AnsiConsole.Write("World");
+
+            // Move the cursor 5 cells to the left.
+            AnsiConsole.Cursor.Move(CursorDirection.Left, 5);
+            AnsiConsole.WriteLine("Universe");
+        }
+    }
+}