- use more modern/cleaner nullability flags

- reorganize properties, update docs

CBAutoScrollLabel/CBAutoScrollLabel.h

@@ -23,7 +23,8 @@ typedef NS_ENUM(NSInteger, CBAutoScrollDirection) {
 @interface CBAutoScrollLabel : UIView <UIScrollViewDelegate>
 
 @property (nonatomic) CBAutoScrollDirection scrollDirection;
-@property (nonatomic) float scrollSpeed; // pixels per second, defaults to 30
+/// Scroll speed in pixels per second, defaults to 30
+@property (nonatomic) float scrollSpeed;
 @property (nonatomic) NSTimeInterval pauseInterval; // defaults to 1.5
 @property (nonatomic) NSInteger labelSpacing; // pixels, defaults to 20
 
@@ -40,13 +41,13 @@ typedef NS_ENUM(NSInteger, CBAutoScrollDirection) {
 @property (nonatomic) CGFloat fadeLength; // defaults to 7
 
 // UILabel properties
+@property (nonatomic, strong, nonnull) UIFont *font;
 @property (nonatomic, copy, nullable) NSString *text;
 @property (nonatomic, copy, nullable) NSAttributedString *attributedText;
 @property (nonatomic, strong, nonnull) UIColor *textColor;
-@property (nonatomic, strong, nonnull) UIFont *font;
+@property (nonatomic) NSTextAlignment textAlignment; // only applies when not auto-scrolling
 @property (nonatomic, strong, nullable) UIColor *shadowColor;
 @property (nonatomic) CGSize shadowOffset;
-@property (nonatomic) NSTextAlignment textAlignment; // only applies when not auto-scrolling
 
 /**
  * Lays out the scrollview contents, enabling text scrolling if the text will be clipped.
@@ -58,12 +59,12 @@ typedef NS_ENUM(NSInteger, CBAutoScrollDirection) {
  * Set the text to the label and refresh labels, if needed.
  * @discussion Useful when you have a situation where you need to layout the scroll label after it's text is set.
  */
-- (void)setText:(NSString * __nullable)text refreshLabels:(BOOL)refresh;
+- (void)setText:(nullable NSString *)text refreshLabels:(BOOL)refresh;
 
 /**
  Set the attributed text and refresh labels, if needed.
  */
-- (void)setAttributedText:(NSAttributedString * __nullable)theText refreshLabels:(BOOL)refresh;
+- (void)setAttributedText:(nullable NSAttributedString *)theText refreshLabels:(BOOL)refresh;
 
 /**
  * Initiates auto-scroll, if the label width exceeds the bounds of the scrollview.