Release v4.0.4

• pug is no longer used to build graph.html for the user interface.
• The minified graph.html for the user interface is now deployed in the
  serve directory with everything else, rather than in templates.
• Memory request information is now reported in the _perf file,
  alongside actual memory usage reporting.
• The scripts used to check whether a job is still running on SGE or
  Slurm clusters are now compatible with python 3.
• The UUID set for the pipestance is now exposed to stage code via the
  MRO_UUID environment variable. The martian helper module for
  python stage code exposes this through the get_pipestance_uuid()
  convenience method.
• Added type hint comments for many of the functions in the martian helper
  module for python stage code. In particular, add NoReturn annotations
  to the martian.throw() and martian.exit() functions, to get better
  results from linting tools on code using those methods.
• Various minor dependency updates.