Work on progress for the new upload server

- Lots of work to make it possible to have several error messages for
  a file parse, use of metfilelib.parser.

- Instead of immediately parsing an uploaded file in the view, it is
  now saved as an UploadedFile, and can be processed in the
  background. There is a new upload page that shows the status of
  uploaded files.

- Some simplifying work, but the way measurement types are tied to
  projects is still far too complicated.