Update readme and code documentation regarding colors

Author: daprice

README.md

@@ -14,6 +14,7 @@ A slider control designed to be easy to grab and use because it can be dragged o
 - Can be dragged or (optionally) tapped to set a value
 - Supports horizontal and vertical orientation in either direction
 - IBDesignable – colors, values, rounded corners, and behavior can be customized in Interface Builder or programatically
+- Supports light & dark appearance using semantic system colors by default (iOS 13+)
 - Adjustable haptic feedback (iOS 10+)
 - VoiceOver support
 

TactileSlider/Classes/TactileSlider.swift

@@ -78,13 +78,15 @@ import UIKit
 
 	/// If true, a single tap anywhere in the slider will set it to that value
 	///
-	/// - Remark: Users may accidentally activate this feature while trying to make very small adjustments. If the context lends to making very small adjustments with the slider, consider disabling this feature.
+	/// - Remark: Users may accidentally activate this feature while trying to make very small adjustments. If the intended use case involves making very small adjustments with the slider, consider disabling this feature.
 	@IBInspectable open var enableTapping: Bool = true
 
 	/// If true, the slider will animate its scale when it is being dragged
 	@IBInspectable open var scaleUpWhenInUse: Bool = false
 
 	/// The color of the track the slider slides along
+	///
+	/// - Important: This defaults to the dynamic system fill color on iOS 13 or greater, but to darkGray on older versions
 	@IBInspectable open var trackBackground: UIColor = {
 		if #available(iOS 13, *) {
 			return .systemFill
@@ -98,6 +100,8 @@ import UIKit
 	}
 
 	/// The color of the value indicator part of the slider
+	///
+	/// - Important: This defaults to a dynamic system color on iOS 13 or greater, but to white on older versions
 	@IBInspectable open var thumbTint: UIColor = {
 		if #available(iOS 13, *) {
 			return .label