System constraints

Replaces stateConstraint method logic with a list of constraint objects for each DrakeSystem.  These can handled more elegantly (preserving the structure of the constraints, and avoiding function handles) by the optimization classes.  

Taking another crack at finishing and merging this (just had a rough time bringing it back in line w/ master).  

Yes, we should not need to modify the documentation.

On Sun, Oct 5, 2014 at 2:37 PM, Russ Tedrake <notifications@github.com>
wrote:

> In solvers/QuadraticConstraint.m:
>
> > @@ -12,7 +12,7 @@
> >        sizecheck(lb,[1,1]);
> >        sizecheck(ub,[1,1]);
> >        nx = size(Q,1);
> > -      obj = obj@Constraint(lb,ub,nx,2);
> > +      obj = obj@Constraint(lb,ub,nx,inf);
>
> i think it's clear...?
> … <#148e199eae98d579_>
> On Oct 5, 2014, at 2:12 PM, Hongkai Dai <notifications@github.com> wrote:
> In solvers/QuadraticConstraint.m: > @@ -12,7 +12,7 @@ >
> sizecheck(lb,[1,1]); > sizecheck(ub,[1,1]); > nx = size(Q,1); > - obj =
> obj@Constraint(lb,ub,nx,2); > + obj = obj@Constraint(lb,ub,nx,inf); So we
> should change the documentation in Constraint constructor, abou grad_level.
> — Reply to this email directly or view it on GitHub.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/RobotLocomotion/drake/pull/464/files#r18436608>.
>