context: 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/D7399

commands: 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/D7398

cmdutil: convert terse status result back to an scmutil.status This is also part of detupling scmutil.status. Differential Revision: https://phab.mercurial-scm.org/D7397