Remove Epsilon equality checking since the animations

dont require such precision.

src/Avalonia.Animation/AnimationsEngine`1.cs

@@ -39,10 +39,10 @@ namespace Avalonia.Animation
 
         public AnimationsEngine(Animation animation, Animatable control, Animator<T> animator, Action OnComplete, Func<double, T, T> Interpolator)
         {
-            if (animation.SpeedRatio <= 0 || DoubleUtils.AboutEqual(animation.SpeedRatio, 0))
+            if (animation.SpeedRatio <= 0)
                 throw new InvalidOperationException("Speed ratio cannot be negative or zero.");
 
-            if (animation.Duration.TotalSeconds <= 0 || DoubleUtils.AboutEqual(animation.Duration.TotalSeconds, 0))
+            if (animation.Duration.TotalSeconds <= 0)
                 throw new InvalidOperationException("Duration cannot be negative or zero.");
 
             _parent = animator;

src/Avalonia.Animation/Animator`1.cs

@@ -59,12 +59,12 @@ namespace Avalonia.Animation
             int kvCount = _convertedKeyframes.Count;
             if (kvCount > 2)
             {
-                if (DoubleUtils.AboutEqual(t, 0.0) || t < 0.0)
+                if (t <= 0.0)
                 {
                     firstCue = _convertedKeyframes[0];
                     lastCue = _convertedKeyframes[1];
                 }
-                else if (DoubleUtils.AboutEqual(t, 1.0) || t > 1.0)
+                else if (t >= 1.0)
                 {
                     firstCue = _convertedKeyframes[_convertedKeyframes.Count - 2];
                     lastCue = _convertedKeyframes[_convertedKeyframes.Count - 1];
@@ -143,11 +143,11 @@ namespace Avalonia.Animation
             // Check if there's start and end keyframes.
             foreach (var frame in _convertedKeyframes)
             {
-                if (DoubleUtils.AboutEqual(frame.Cue.CueValue, 0.0))
+                if (frame.Cue.CueValue == 0.0d)
                 {
                     hasStartKey = true;
                 }
-                else if (DoubleUtils.AboutEqual(frame.Cue.CueValue, 1.0))
+                else if (frame.Cue.CueValue == 1.0d)
                 {
                     hasEndKey = true;
                 }

src/Avalonia.Animation/Utils/DoubleUtils.cs

@@ -1,16 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-
-namespace Avalonia.Animation.Utils
-{
-    internal static class DoubleUtils
-    {
-        internal static bool AboutEqual(double x, double y)
-        {
-            double epsilon = Math.Max(Math.Abs(x), Math.Abs(y)) * 1E-15;
-            return Math.Abs(x - y) <= epsilon;
-        }
-    }
-}

src/Avalonia.Animation/Utils/EasingUtils.cs

@@ -13,6 +13,6 @@ namespace Avalonia.Animation.Utils
         /// <summary>
         /// Half of <see cref="Math.PI"/>
         /// </summary>
-        internal static double HALFPI = Math.PI / 2d;
+        internal const double HALFPI = Math.PI / 2d;
     }
 }