Merge branch 'head-propagate'

CMakeLists.txt

data/cone.obj

data/plane.mtl

data/plane.obj

data/sphere.obj

data/sphere_normal_test.obj

data/susanne.obj

data/test.obj

data/test_small.obj

renders/rename_png_to_bmp.py

src/geometries/Geometry.h

src/geometries/ObjGeometry.cpp

src/geometries/ObjGeometry.h

src/geometries/PBDSimulation.cpp

src/geometries/ParamSurface.cpp

src/geometries/ParamSurface.h

src/geometries/VertexData.cpp

src/geometries/VertexData.h

src/main.cpp

src/objects/HeadObject.cpp