CMAKE_PREFIX_PATH now pointing to C:\opt\x64; no more need to point to include and lib subdirectories separately

reintegrate directory ff under Sample/

See merge request !507

Corrections and simplifications

See merge request !497

Refactorings in Particle context

See merge request !499

rm unused

See merge request !496

Autoformatting

See merge request !495

Remove SessionModel/SessionItem from MaterialModel/MaterialItem

See merge request !494

the materials are not deleted and created any more after closing the material selection dialog => no need to take care of material deletion