Add global usings (#668)

* Use global usings

* Fix namespace declarations for test projects

src/Spectre.Console/Live/LiveDisplay.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Threading.Tasks;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/LiveDisplayContext.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/LiveDisplayRenderer.cs

@@ -1,6 +1,3 @@
-using System.Collections.Generic;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 internal sealed class LiveDisplayRenderer : IRenderHook

src/Spectre.Console/Live/LiveRenderable.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
 using static Spectre.Console.AnsiSequences;
 
 namespace Spectre.Console.Rendering;

src/Spectre.Console/Live/Progress/Columns/DownloadedColumn.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Globalization;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/ElapsedTimeColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/PercentageColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/ProgressBarColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/RemainingTimeColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/SpinnerColumn.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Linq;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/TaskDescriptionColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Columns/TransferSpeedColumn.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Globalization;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Progress.cs

@@ -1,8 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/ProgressColumn.cs

@@ -1,6 +1,3 @@
-using System;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/ProgressContext.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/ProgressRefreshThread.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Threading;
-
 namespace Spectre.Console;
 
 internal sealed class ProgressRefreshThread : IDisposable

src/Spectre.Console/Live/Progress/ProgressRenderer.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 internal abstract class ProgressRenderer : IRenderHook

src/Spectre.Console/Live/Progress/ProgressSample.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Spectre.Console;
 
 internal readonly struct ProgressSample

src/Spectre.Console/Live/Progress/ProgressTask.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/ProgressTaskState.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Progress/Renderers/DefaultProgressRenderer.cs

@@ -1,9 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 internal sealed class DefaultProgressRenderer : ProgressRenderer

src/Spectre.Console/Live/Progress/Renderers/FallbackProgressRenderer.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 internal sealed class FallbackProgressRenderer : ProgressRenderer

src/Spectre.Console/Live/Progress/Renderers/FallbackStatusRenderer.cs

@@ -1,8 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using Spectre.Console.Rendering;
-
 namespace Spectre.Console;
 
 internal sealed class FallbackStatusRenderer : ProgressRenderer

src/Spectre.Console/Live/Progress/Spinner.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Status/Status.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Threading.Tasks;
-
 namespace Spectre.Console;
 
 /// <summary>

src/Spectre.Console/Live/Status/StatusContext.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Spectre.Console;
 
 /// <summary>