V 2.0.0 (⚠️ Important)

• Fix Issue 5, thx MVakas!

• Modify some of the properties' name and methods' name:

  // Properties' name.
  @property (nonatomic, assign) CGFloat timerInterval;
  ->
  @property (nonatomic, assign) CGFloat timeInterval;
  
  @property (nonatomic, copy  ) NSString  *placeholderImage;
  ->
  @property (nonatomic, copy  ) NSString  *placeholderImageName;
  
  // All methods' name.
  timerInterval -> timeInterval
  placeholderImage -> placeholderImageName