an option to enable only horizontal or vertical scrollbars

this gives 2 extra options for enabling only the vertical or horizontal scrollbars 
(enableScrollbars to false and then enableVerticalScrollbar to true)

I kept the enableScrollbars for backwards compatibility, but i gues that can be fully removed so that you only have 2 options 
If you set only `enableScollbars`, would this change not mean that it won't work?  Does it need some sort of `|| enableScrollbars`?