Fixed bug in k-charge implementation for J-algorithm
Trac #15444: Two algorithms for k-charge do not give same answer

Currently, the two implementations of k-charge do not give the same
answer:
{{{
sage: T =
WeakTableaux(4,[4,3,2,1],[2,2,2,2,1,1],representation='bounded')
sage: for t in T:
    print t.k_charge(), t.k_charge(algorithm='J')
....:
9 10
10 10
8 8
9 9
10 10
8 9
11 11
}}}
Comparing against the expansion of Hall-Littlewood symmetric functions
in terms of k-Schur functions, it seems that the I-implementation is
correct
{{{
sage: Sym = SymmetricFunctions(QQ['t'])
sage: Qp = Sym.hall_littlewood().Qp()
sage: ks = Sym.kschur(4)
sage: ks(Qp[2,2,2,2,1,1])[Partition([4,3,2,1])]
t^11 + 2*t^10 + 2*t^9 + 2*t^8
}}}

Compared to the book http://arxiv.org/abs/1301.3569 pg. 84
the bug seems to be in the method _height_of_restricted_subword in
k_tableau.py.

URL: http://trac.sagemath.org/15444
Reported by: aschilling
Ticket author(s): Anne Schilling
Reviewer(s): Mike Zabrocki