bug fix: ui.resizable >> !respecting min height || width

bug fix: ui.resizable >> !respecting min height || width

<div dir="ltr">I was not sure where to post in the bug tracker, forum or email.  The UI site stated that emailing gets a fast response, so here it is.
version: 1.6b
ui.resizable >> this._respectSize
bug: min height || width is not respected when the data.height === 0 as calculated from this._change passed from this.mouseDrag
result: box jump the size of min height || width since data.height=0 gets passed through
fix:
(1) add new function to 'this' to detect nothing but allow zero
this._isNothing: function(x) {return x === undefined || x === null},
(2) _respectSize:
            isminw = !this._isNothing(data.width) && (o.minWidth && data.width < o.minWidth),
            isminh = !this._isNothing(data.height) && (o.minHeight && data.height < o.minHeight);
if this has not been addressed, please put in next release.
regards,
recrit
</div>