D1238: overlayworkingctx: add _manifest, files(), added(), removed(), modified()

[phillco (Phil Cohen)]

phillco added a comment.


  OK, kept it in and passing to `man.setflag()`.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D1238

To: phillco, #hg-reviewers, durin42
Cc: mercurial-devel