Remove wpsc_core_store_use_shipping() in favor of wpsc_is_shipping_enabled()
Clear temporary data, whether in cache or in transient
* Checks options tables for transients and delete them if appropriate
* Fires action hooks so themes, classes, plug-ins, shipping modules all can know when data needs to be cleared, or has been cleared
* Updated functions to use new clear data function rather than just wp_clear_cache