Some $(this) -> $this caching. Still about performance.
adds callback for each image upon load. happens independently of effect
Add data_attribute option to allow customization of image url attribute
Merge branch 'patch-2' of https://github.com/vzwick/jquery_lazyload into 1.7.0
Merge branch 'master' of https://github.com/ifightcrime/jquery_lazyload into 1.7.0
Pass number of images left and settings to callback.

    $("img.lazy").lazyload({
        callback : function(elements_left, settings) {
            console.log(this, elements_left, settings);
        }
    });
Make caching code look more elegant.
Merge branch 'master' of https://github.com/bryanchow/jquery_lazyload into 1.7.0

Conflicts:
	jquery.lazyload.js
Update header.
Shortscope and cache window object.
Purge images only when they are lazyloaded. Not everytime scroll is triggered.
Fix number of elements left for the first call of callback.
Add event "appear" which is called when image appears before it is loaded.

$("img.lazy").lazyload({
    appear : function(elements_left, settings) {
    console.log(this, elements_left, settings);
});
Rename callback to load. Follows jQuery UI style event naming.

$("img.lazy").lazyload({
    load : function(elements_left, settings) {
    console.log(this, elements_left, settings);
});
Rename effectspeed to effect_speed. Rename above-the-fold to above-the-top, right-of-fold to right-of-screen left-of-fold to left-of-screen and add in-viewport.
Update README for 1.7.0.
Remove old effectspeed from parameters.
Update minified versions.
Remove default effect speed. Undefined means no effect.
Use uniform style for contributor names.