active-set LCP

implements an active-set method for LCP time-stepping using the fastQP algorithm

resolves #510
excellent.  

On Dec 19, 2014, at 2:35 PM, Scott Kuindersma <notifications@github.com> wrote:

> In systems/plants/test/contactSensorTest.m:
> 
> > @@ -4,6 +4,7 @@
> >  options.floating = true;
> >  options.twoD = true;
> >  options.terrain = RigidBodyFlatTerrain;
> > +options.enable_fastqp = false; 
> Yes, on second glance, this is another bullet normal issue. At some point during the simulation when the brick is resting on the ground, the normals are wrong and this gets carried along to the end because the active set still works. Re-enabling fastQP and disabling bullet fixes it
> 
> —
> Reply to this email directly or view it on GitHub.
>