anyplugins - global pointer to app

The plugins need to be able to get to the contents of the app
instantiation. This is a temp solution till something more elegant can
be found.
checkout - bug fix

when an item with zero inventory is in the cart and inventory settings
say no checkout on zero inventory items, item should be removed from the
cart. This wasn't happening.
anyplugins - update to point to new global app ref.