Adding events for pull threshold

[ghost]

If you want some events to happen when the pull threshold is exceeded (or reversed) - Here is some code.

I know I should do a pull request - but for now, if you want to patch this in go ahead

We are using this to trigger a slight vibration on a mobile device when the threshold is exceeded.

`--- a/www/js/libraries/xpull.js +++ b/www/js/libraries/xpull.js @@ -47,6 +47,8 @@ scrollingDom: null, // if null, specified element onPullStart: function() {}, onPullEnd: function() {},

•        onPullThreshold: function() {},
  

•        onPullThresholdReverse: function() {},
         callback: function() {}
     };
  

@@ -126,8 +128,10 @@

                 if (top > that.options.pullThreshold && !hasc) {
                     that.indicator.addClass('xpull_pulled');

•                    that.options.onPullThreshold.call(this);
                 } else if (top <= that.options.pullThreshold && hasc) {
                     that.indicator.removeClass('xpull_pulled');
  

•                    that.options.onPullThresholdReverse.call(this);
                 }
  
             } else {
  

`