Bug fix

- Scaling factors now correspond to domain size and young modulus
- Use of cases completely removed.
- Surface_values method is now deprecated
- output_surface is the new method to get surface values(It still needs
work)
New feature

- Outputting surface data is now completely independent of node
placements.
- Old surface_values can be removed.(Kept for more testing)
New Scripts

Two scripts to plot using gnu plot
bugfix