Added psyco.proxy2 function, which replaces the func_code object of a function with a new code object which subsequently calls the psyco proxy function.  Future selective compilation will use psyco.proxy2, although this is not enabled right now.
Added psyco.proxy2 function, which replaces the func_code object of a
function with a new code object which subsequently calls the psyco proxy
function.  Future selective compilation will use psyco.proxy2, although
this is not enabled right now.

NOTE: This code still requires testing and lacks proper error checks
(just a bunch of asserts right now).

tonysimpson/Ni,tonysimpson/Ni,tonysimpson/Ni,tonysimpson/Ni,tonysimpson/Ni