Clean up public API

* Make things a bit more consistent
* Add extension methods to configure things like tables, panels and grids.

src/Spectre.Console.Tests/Unit/PanelTests.cs

@@ -81,7 +81,7 @@ namespace Spectre.Console.Tests.Unit
             // Given
             var console = new PlainConsole(width: 80);
             var text = new Panel(
-                Text.Markup("I heard [underline on blue]you[/] like 📦\n\n\n\nSo I put a 📦 in a 📦"));
+                new Markup("I heard [underline on blue]you[/] like 📦\n\n\n\nSo I put a 📦 in a 📦"));
 
             // When
             console.Render(text);

src/Spectre.Console.Tests/Unit/TextTests.cs

@@ -10,20 +10,26 @@ namespace Spectre.Console.Tests.Unit
         [Fact]
         public void Should_Consider_The_Longest_Word_As_Minimum_Width()
         {
+            // Given
             var text = new Text("Foo Bar Baz\nQux\nLol mobile");
 
+            // When
             var result = ((IRenderable)text).Measure(new RenderContext(Encoding.Unicode, false), 80);
 
+            // Then
             result.Min.ShouldBe(6);
         }
 
         [Fact]
         public void Should_Consider_The_Longest_Line_As_Maximum_Width()
         {
+            // Given
             var text = new Text("Foo Bar Baz\nQux\nLol mobile");
 
+            // When
             var result = ((IRenderable)text).Measure(new RenderContext(Encoding.Unicode, false), 80);
 
+            // Then
             result.Max.ShouldBe(11);
         }