patch: use field names instead of field numbers on scmutil.status
As part of my pytype adventures I want to make scmutil.status no longer a
subclass of tuple. This is part of that process.
Differential Revision: https://phab.mercurial-scm.org/D7401
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.