Minor improvements
@osander: Can you have a look? This MR includes:
- Print total time needed for the whole program to run (in main), total assembly time and total time needed for solving
- Refine only the Surfaceshell boundary, not the rest of the elastic material
- Add exception handling when computing the energy after the trust region step
- Continue with Trust-Region-Algorithm by if IPOPT threw an error (catch it and then continue with a smaller TR-radius)
Edited by Nebel, Lisa Julia