Also adds safegaurds to check if the pointers for linear proj constraints are not set

ENH: implemented a clearing function for line mesh and improved description for setting the color of a material

Also enforces formatting

Also, move constructor of VTKViewer to .cpp

Use already defined enums as arguments

launchSimulation and startSimulation have similar meaninn to be included in public API.
Moved the launch simulation to be a private member.

The simulation can now be set to either instantiate:
  - A regular simulation using vtkRenderWindow
  - A VR simulation using vtkOpenVRRenderWindow

To do so, the simulation manager can be set to be a VR simulation
when initialized. The default comportment will be a regular simulation.

This is needed for the VROrthognathic/OrthognathicTrainer project.

CLEANUP: added ability to expand surface meshes, abstracted interactor, and fixed transforms in Vulkan renderer