Solving #19 (and possibly #29). Bypassing jQuery UI bug.

Solving #19 (and possibly #29).
Provides the extra option "floating" to ui-sortable options.
(This is to bypass [jquery-ui known issue](http://bugs.jqueryui.com/ticket/7498).)

The default value is undefined, and has no effect.
If floating is set to true (or false), then jquery.ui.sortable plugin is forced to behave as if the list was horizontal (or vertical respectively).
[Example pen](http://codepen.io/thgreasi/pen/aKeru)