Get parallel and serial file writing matching after reorder

[kuberry]

Original data has fields copied to new file which had parts written in parallel. Original fields are never mixed up, so they don't need resorted. New data that was added needs resorted according to ID, but this is difficult to check.

Need to create a test that writes a fake data field (or recopy the lat/lon field, e.g.) and then do comparison at the end to verify correct functionality.

[kuberry]

While this test should still be created, parallel and serial netCDF outputs currently match to single precision.

An additional test would be to print the solution with double precision for a particle DOF# at a particular iteration #, and then to compare to see if they truly differ after serial precision, or whether they are the same but the difference comes from writing to file.