switch to new quenchers

They should be fully compatible with the old quenchers.  If function
getEnergyGradient is passed it is wrapped to create a potential object.
They return Results objects, but some functions have been overloaded to
act like lists in some ways
get rid of _quench_new references
MC and basinhopping now keep track of lowest energy and coords

add test function for basinhopping

remove a test using scipy.boost.weave