Add interlace powerpoint image touch #76 [skip ci]

tests/ImageSharp.Tests/FileTestBase.cs

@@ -33,6 +33,7 @@ namespace ImageSharp.Tests
             // TestFile.Create(TestImages.Png.Blur), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.Indexed), // Perf: Enable for local testing only
             TestFile.Create(TestImages.Png.Splash),
+            TestFile.Create(TestImages.Png.Powerpoint),
             // TestFile.Create(TestImages.Png.SplashInterlaced), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.Interlaced), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.Filter0), // Perf: Enable for local testing only

tests/ImageSharp.Tests/TestImages.cs

@@ -19,6 +19,7 @@ namespace ImageSharp.Tests
             public const string Blur = "Png/blur.png";
             public const string Indexed = "Png/indexed.png";
             public const string Splash = "Png/splash.png";
+            public const string Powerpoint = "Png/pp.png";
 
             public const string SplashInterlaced = "Png/splash-interlaced.png";