Add dependency to rply
Add convex hull
Add mechanism to handle internal piecewise primitives and use them to control primitive sampling using isInside method
Change default value of ponctualSampler::z position = 0
Add addSample method in VisibleSampler, calling Primitive::isInside before addin the sample
Change UI to load 3D meshes
Add mechanism to load a ply using rply.
Here the associated primitives are not created (TODO)
Fix commited git conflict