Allow for callback functions to override default behavior

Callback functions might include:

• onLoad, called when the we are starting the ajax request
• onSuccess, called when a new page is successfully loaded
• onFailure, called when a error occurs when trying to load the next page
• onInsert, called when a new item should be inserted
• onLastPage, called when the last page is loaded

[fieg]

Added onLoadItems callback. I don't think the other callback functions I suggested earlier are really usefull.

[VerbHQ]

Actually ignore this, I've made some small amends for it to do as I needed, if you want to integrate you're welcome

Hey Fleg,

Love your plugin, but I would say that one missing call back is an onComplete state. onLoadItems does half the job, but running functions on completion of the content being inserted into the container would certainly be helpful.

Thanks for your wonderful Plugin and all the hard work you've put into it!

Andy