New Sortable option to specify horizontal or vertical floating mode

Hi,

I could be a little but useful feature: Give (to the sortable's user) the possibility to specify horizontal or vertical floating mode when creating sortable widget.

When you don't want to have items when sortable is initialized, floating mode is set by default to vertical :

jquery.ui.sortable.js - line 53

this.floating = this.items.length ? (/left|right/).test(this.items[0].item.css('float')) : false;

Maybe an new option ('floating') which overrides the computing floating mode above should be helpful for addressing this case.

Regards