Add a functionality of removing skeleton from world
Merge branch 'origin/master'

Conflicts:
	src/constraint/ConstraintDynamics.cpp
	src/dynamics/Joint.cpp
	src/dynamics/Joint.h
	src/dynamics/Skeleton.h
Fix updating mBodyIndexToSkelIndex in ConstraintDynamics::removeSkeleton()
Add functionality of spawning/deleting cubes for "cube" app
Merge branch 'origin/master'
Merge branch 'origin/master'

Conflicts:
	src/collision/CollisionDetector.cpp
	src/collision/CollisionDetector.h
	src/constraint/ConstraintDynamics.cpp
	src/constraint/ConstraintDynamics.h
Fix BodyNode::getWorldCOM
Fix compiler error caused by last commit
Merge pull request #112 from dartsim/removing_skeleton_functionality

Add a functionality of removing skeleton from world
Remove Skeleton::updateForwardKinematics()

BodyNode::updateTransform() and updateVelocity() are called when the user sets the state of the skeleton.
updateEta() and updateAcceleration() are called by the dynamics algorithm when needed.
Merge branch 'master' of github.com:dartsim/dart
Adapt balance app to last commit's changes
Move SimWindow from simulation to yui
Remove old unused version of Skeleton::computeInverseDynamicsLinear()
Call computeEquationsOfMotionID() in World::addSkeleton() because some controller need equation of motion especially M, M^{-1} to calculate control input at the beginning of simulation.
Remove boost from header files

This way boost-dev is no longer a development dependency of DART.
Merge branch 'master' of github.com:dartsim/dart
Remove boost headers from SkelParser
- Clean up joints
- Remove kinetic energy and potential energy parts from Skeleton and joints since there are not implemented yet.
Change CMake files two build 2 dart libraries