std:: missing before pair in /u/numer/baroli/LifeV-source/lifev/lifev/structure/solver/StructuralOperator.hpp

Adding a single source file for all the exporter types. I am going to remove the other test on the importer

Correctly split the export and import. Export also has import to check that the results are correctly printed.

Previous commits by Davide Baroli were wrong. The attempt to reset to the original settings has failed. Resetting the missing pieces.