changes to allow simplecart properties, options, + others 

- element properties now allow u to set the simplecart properties (this is done when adding element to app)
- in properties can also nominate the zoo elements used for cart item data (for example price, image, options)
- I added two new elements Option Select & Quantity, these allow front end input. 
- I moved simplecart.js into the element, so no longer have to modify the template 
- updated the modules for joomla 3 +