Improve computation time on the SOFA scene

[bakpaul]

The scene Experimental/newSofaMain_v0.2.scn requires a bit of optimization to run smoothly on any middle range computer (>=40 FPS). This issue's goal is to give ideas on how to improve them.

Here is a first list

• Use Asynch LDL solver on the logo
  • Bad idea, not stable with user interaction
• Remesh the logo
• Remesh the O collision model
• Use unbuilt GS
  • Unstable and unfit to use with LinearSolverConstraintCorrection
• Use a centerline as collision model for one or several objects
• Decrease the number of sphere collision ( < nb dofs)
• Add topological change (possibly using the TopologicalChangeProcessor)