conjuncts() and disjuncts() need to be recursive

[GoogleCodeExporter]

I was playing with the Criminal(West) example and the new fol_bc_ask()
stuff, couldn't get it to work unless I changed conjuncts() as follows:

def conjuncts(s):
    if isinstance(s, Expr) and s.op == '&':
        r = []
        for arg in s.args:
            r.extend (conjuncts (arg))
        return r
    else:
        return [s]

Without this change, conjuncts() will do this:
>>> conjuncts (sar.args[0])
[((American(v_1) & Weapon(v_2)) & Sells(v_1, v_2, v_3)), Hostile(v_3)]

Original issue reported on code.google.com by rushing....@gmail.com on 2 Mar 2009 at 6:53