Bound index to number of children.

Because of imprecisions in calculating the index, it would sometimes be
out of bounds on the upper end too, so this max/min combination
constrains it between 1 and number of children.
Vertical scrubbing direction added.

There is a combined option as well, which chooses from horizontal or
vertical direction, depending on the side from which you move the mouse
in.
Direction selection bug fix.
Better combined direction handling.

Now the active direction can switch depending on the current direction
you’re moving.
More compact code.
Added some files to .gitignore file
Merge branch 'master' of https://github.com/Retronator/iscrubber into Retronator-master
Merge branch 'master' of https://github.com/Retronator/iscrubber into develop
Change DIRECTION variable name to _direction
Remove hideWithClass option, it's always necessary hide the elements
Update README file
Updated README file
Added minified version