Added methods for adding, removing and getting items in the carousel

I have added internal methods for adding, removing and getting items from the carousel. Adding and removing methods have some custom events like the way you have written other methods. Kindly review the code and add it.

P.S: Though adding and removing the items can be done using jquery and manually calling 'reload' method, i strongly believe that the author should provide a way internally. By the way, really awesome coding. I am still learning the way you implemented it. Lots of difference in the way the code has written from 0.2 to 0.3. Good job.