Added args for Hx and HJacobian.
Added args for Hx and HJacobian.

The old way of forcing the functions to own variables was stupid
and unpythonic. Now I know better.

BrianGasberg/filterpy,aitatanit/filterpy,rlabbe/filterpy,Censio/filterpy,rlabbe/filterpy,Censio/filterpy,aitatanit/filterpy,BrianGasberg/filterpy