Make YCbCr.(Y/Cb/Cr) and Hsv.(H/S/V) a plan field to make color manipulations a bit faster

Former-commit-id: 68972e8996c91cc0a2f477aa18cb2be8401e1ccb
Former-commit-id: 858f463b331210bbdea7548447c0ad7a2fa2a658
Former-commit-id: 2faf9054b4f9cdb9acfe22019db9026024f1571d

src/ImageProcessor/Colors/Hsv.cs

@@ -45,28 +45,27 @@ namespace ImageProcessor
         /// Gets the H hue component.
         /// <remarks>A value ranging between 0 and 360.</remarks>
         /// </summary>
-        public float H { get; }
+        public readonly float H;
 
         /// <summary>
         /// Gets the S saturation component.
         /// <remarks>A value ranging between 0 and 100.</remarks>
         /// </summary>
-        public float S { get; }
-
-
+        public readonly float S;
+        
         /// <summary>
         /// Gets the V value (brightness) component.
         /// <remarks>A value ranging between 0 and 100.</remarks>
         /// </summary>
-        public float V { get; }
+        public readonly float V;
 
         /// <summary>
         /// Gets a value indicating whether this <see cref="Hsv"/> is empty.
         /// </summary>
         [EditorBrowsable(EditorBrowsableState.Never)]
         public bool IsEmpty => Math.Abs(this.H) < Epsilon
-                               && Math.Abs(this.S) < Epsilon
-                               && Math.Abs(this.V) < Epsilon;
+                            && Math.Abs(this.S) < Epsilon
+                            && Math.Abs(this.V) < Epsilon;
 
         /// <summary>
         /// Compares two <see cref="Hsv"/> objects. The result specifies whether the values

src/ImageProcessor/Colors/YCbCr.cs

@@ -49,27 +49,27 @@ namespace ImageProcessor
         /// Gets the Y luminance component.
         /// <remarks>A value ranging between 0 and 255.</remarks>
         /// </summary>
-        public float Y { get; }
+        public readonly float Y;
 
         /// <summary>
         /// Gets the Cb chroma component.
         /// <remarks>A value ranging between 0 and 255.</remarks>
         /// </summary>
-        public float Cb { get; }
+        public readonly float Cb;
 
         /// <summary>
         /// Gets the Cr chroma component.
         /// <remarks>A value ranging between 0 and 255.</remarks>
         /// </summary>
-        public float Cr { get; }
+        public readonly float Cr;
 
         /// <summary>
         /// Gets a value indicating whether this <see cref="YCbCr"/> is empty.
         /// </summary>
         [EditorBrowsable(EditorBrowsableState.Never)]
         public bool IsEmpty => Math.Abs(this.Y) < Epsilon
-                               && Math.Abs(this.Cb) < Epsilon
-                               && Math.Abs(this.Cr) < Epsilon;
+                            && Math.Abs(this.Cb) < Epsilon
+                            && Math.Abs(this.Cr) < Epsilon;
 
         /// <summary>
         /// Compares two <see cref="YCbCr"/> objects. The result specifies whether the values