Need to add new options: 1. `contentClass` - adds a class to content element 2. `containerClass` - adds a class to container element 3. `scrollbarClass` - adds a class to scrollbar class 4. `alwaysShow` - always shows the scrollbar.
Need to add new options:
contentClass- adds a class to content elementcontainerClass- adds a class to container elementscrollbarClass- adds a class to scrollbar classalwaysShow- always shows the scrollbar.