Add Paraview compatible file to visualize all the generated results.

[lmdiazangulo]

• Remove _prescribed_and_res_floating Paraview exporting due to large size of files.
• Generate a file which can be opened in paraview (I think it is called pvd) which opens the results for all conductors, including electrostatic and magnetostatic results.
• If floating potentials have been computed, rather than exporting prescribed_and_rest_floating results, it adds a file which can be opened in Paraview which loads the corresponding floating potentials into each conductor.

[lmdiazangulo]

Not for now.