Add selection option

This will be good if the cells selection is set as an option. For example:

 defaultOptions = {
     highlightHorizontal: null,
     highlightVertical: null,
     selection: 'td, th'
 };

And in code:

table.on('mouseenter', options.selection, function () {
...
}

table.on('mouseleave', options.selection, mouseleave);

So user can decide wich cells are processed.

$('table').wholly({
    highlightHorizontal: 'horizontal-class-name',
    highlightVertical: 'vertical-class-name',
    selection: 'td:not(".skip")'
})