As discussed in #153

My suggestion is leave the 'wpsc_save_cart_item' action alone so we
don't break anything ,deprecate it.

Add a do_action('wpsc_before_save_cart_item', $cart_id, $this ) call
before the cart item record and cart meta is stored into the DB.

Add a do_action('wpsc_after_save_cart_item', $cart_id, $this ) call
after the cart item record and cart meta is stored into the DB.
leave the 'wpsc_save_cart_item' action alone so we don't break anything
,deprecate it.

Add a do_action('wpsc_before_save_cart_item', $cart_id, $this ) call
before the cart item record and cart meta is stored into the DB.

Add a do_action('wpsc_after_save_cart_item', $cart_id, $this ) call
after the cart item record and cart meta is stored into the DB.

Fixed indentation on one line 

As discussed in #154, pull request #153