Adding the box and ball example to sampling_based_c3_public

[sharanyashastry]

Once the T-PR is merged as described in #373 , the following changes will need to be done if we want to bring back the box and ball examples.

Add this folder back for the box and this for the ball.

The box example is currently set up as more than a planar pushing example but doesn't work since I couldn't tune it to get it to topple the box. To make it strictly planar again, keep only kQuat_6 among these). The same changes as for the T apply here in terms of constraints.

The last working state of the ball example is here. The controller has however diverged a lot since. I've tried to bring it up to date such that everything builds but the controller hits a gurobi exception that I didn't manage to get to.