Add an ability to trigger `columnizeIt` of selected element from external scope

[Finesse]

Sometimes there is a need to rebuild columns of selected element when window is not resized. Now there is no way to do it.

This feature can be added by adding $inBox.data("columnize", columnizeIt); somewhere near line 142. In this case it would work like this:

$('#columns').columnize();
// some time later...
$('#columns').data('columnize')();

It is the easiest way to add this feature but it is dirty way. So it would be great if there is a more elegant way to do rebuilding.