Swap lines in update function

[davedupplaw]

From website comment:

Just to tell you that on function _update you should switch the lines inside step function like this.

_update: function() {
var self = this;
var valueProperty = {val: this.currentValue};
$(valueProperty).animate( {val: this.valueToAttain}, {
duration: this.options.animationSpeed,
step: function() {
self.currentValue = this.val;
self._updateViewToValue(this.val);
}
} );
},

Need to look into whether this is correct.