fix for grad with pos control and test
updating resolveConstraints to use new optimization classes
Use btConvexHullShape for boxes.

The convex interface that we're using for our closest-distance computations
gives erroneous normals for box shapes. If we represent the box as the convex
hull of its vertices the normals are fine. Fixes #174.
Add test case for box-point contact normals
Update contactImplicitBrick test.

Changes:
  * Removes terrain-only flag.
  * Disable visualization by default
  * Check positions and velocities with different tolerances (as per Michael's
    email)

Now passes with tolerances 1e-2 for positions 1e-1 for velocities.
Fixed bug in RigidBodyTorsionalSpring where spring torque was only applied to the child body (and not the parent).
Merge branch 'drake-origin/master'
removed persistent variable
fixed typo
Merge pull request #271 from kuindersma/fix-poly-no-mail-typo

fixed typo in AffineSystem
Changed quat methods to return a value instead of working with references.
drakeQuatUtil --> drakeGeometryUtil.
Merge pull request #272 from tkoolen/drakeQuatUtil-updates

Drake quat util updates
fixed typo causing quadrotor unit test to fail
Merge branch 'poscontrol' of https://github.com/blandry/drake
use valuecheck in test
Slightly increase tol in contactImplicitBrick.
implemented window resizing and value displays in inspector to make it a little more usable
Use rel. tol. 1e-8 in ModelTest.cpp
Merge pull request #273 from kuindersma/fix-pelvis-bug

removed persistent variable