Registers a `Storable` instance in the global service.

def hdf5_storable(type_or_storable, *args, **kwargs):
    '''Registers a `Storable` instance in the global service.'''
    if not isinstance(type_or_storable, Storable):
        type_or_storable = default_storable(type_or_storable)
    hdf5_service.registerStorable(type_or_storable, *args, **kwargs)