Javascript refactoring

[frankban]

Must:

• use $.endlessPaginate syntax;
• handle onScroll as an option;
• add ability to attach callbacks;
• use selectors to decide what elements need to be paginated, and how;
• maintain backward compatibility.

[frankban]

Also avoid on scroll duplicate calls.
marcofucci said in google code:

With some browsers, you might have duplicate ajax calls triggered if you're using the twitter approach.
The problem also appears if an ajax request takes several seconds.

To avoid that, just check if a previous call is in progress:

endless.js

Add:

if (loading.is(':visible')) {
return;
};

after:

var container = $(this).closest(".endless_container");
var loading = container.find(".endless_loading");

[frankban]

JavaScript refactoring done and documented.