Introduced 'Finalized' attribute in the NetCDF file

 - is set to 0 at beginning of run, and to 1 at the finalization.
 - field_transform.f90 checks for it being 1 at the beginning and waits for 60s, if it's still 0.
 - attribute 'percent completed' stores the progress of the calculation (is only updated once a strain dump is done, so slightly lagging behind)