fix: path resolving was wrong when built as a subproject

Signed-off-by: Filip Wasil <filip.wasil@gmail.com>
Compile fix for parallelLinearBvh.cl on OS X Intel HD 5000
Merge pull request #196 from jackoalan/parallel_linear_bvh_cl_fix

Compile fix for parallelLinearBvh.cl on OS X Intel HD 5000
Merge pull request #187 from filipwasil/subproject_build_fix

fix: path resolving was wrong when built as a subproject
Merge pull request #212 from erwincoumans/master

dynamic loading of OpenGL/X11
add improved btGeneric6DofSpring2Constraint, thanks to Puhr Gabor and Tamas Umenhoffer!
improved the new demo testbed (work-in-progress)
add basic Lua demo, import URDF test, STL import, obj import