_clang-format file and applied to HelloWorld.cpp
usage:
clang-format -style=file -i examples/HelloWorld/HelloWorld.cpp
THere are still some issues with clang-format and its style
- explain in comments the shape of the ground and better group that code
- give enough time for the sphere to hit the ground
- don't ask for confirmation to exit, it's annoying
add sphere2.urdf
move btSpatialAlgebra into LinearMath
remove some warnings, introduce BT_ZERO, BT_ONE, BT_HALF as defines for 0.f/0., 1.f/1., 0.5f/0.5 respectively
