remove some redundant usings (#976)

Author: SimonCropp

src/ImageSharp/Advanced/AotCompilerTools.cs

@@ -9,7 +9,6 @@
 using SixLabors.ImageSharp.Processing.Processors.Dithering;
 using SixLabors.ImageSharp.Processing.Processors.Quantization;
 using SixLabors.ImageSharp.Processing.Processors.Transforms;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp.Advanced
 {

src/ImageSharp/Common/Helpers/Guard.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -6,7 +6,6 @@
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using System.Text;
 
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Memory;

src/ImageSharp/Formats/Png/IPngDecoderOptions.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using System.Text;
-
 namespace SixLabors.ImageSharp.Formats.Png
 {
     /// <summary>

src/ImageSharp/Formats/Png/PngDecoder.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.IO;
-using System.Text;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Png

tests/ImageSharp.Tests/Drawing/Text/DrawText.cs

@@ -3,11 +3,9 @@
 
 using System.Numerics;
 using SixLabors.Fonts;
-using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Processing;
 using SixLabors.ImageSharp.Processing.Processors.Text;
 using SixLabors.Primitives;
-using SixLabors.Shapes;
 using Xunit;
 
 namespace SixLabors.ImageSharp.Tests.Drawing.Text

tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Text;
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Metadata;

tests/ImageSharp.Tests/Formats/Gif/GifMetaDataTests.cs

@@ -4,7 +4,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Text;
 
 using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Metadata;

tests/ImageSharp.Tests/MetaData/ImageMetaDataTests.cs

@@ -1,9 +1,6 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using System.Collections.Generic;
-
-using SixLabors.ImageSharp.Formats.Gif;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;

tests/ImageSharp.Tests/MetaData/Profiles/Exif/ExifProfileTests.cs

@@ -7,7 +7,6 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;