Remove robotics::World and robotics::Robot

Use simulation::World and dynamics::SkeletonDynamics instead.
Add more collision test to testCollision
- box-sphere
- sphere-sphere (weired contact point)
Fix compile error in testCollision.cpp and commented out sphere-sphere collision test (failed to pass).
Add more collision tests to testCollision.
Commented out failed collision tests.
Merge branch 'origin/master'

Conflicts:
	src/robotics/World.cpp