Fix, when scrollbar height equal parent height, auto hide scrollbar and railbar if exist

Some times, scrollbar height not identically equal parent height when should, it like this:

    barHeight === 249.02;
    me.outerHeight() === 250;

I think using 'me.outerHeight() - barHeight <= 1' is good.

And, when scrollbar height equal parent height, scrollbar and railbar if exist should auto hide, I fix it.