D6487: states: created new class to handle multi-step operation states

[taapas1128 (Taapas Agrawal)]

taapas1128 added a comment.


  @martinvonz Is it alright now?

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D6487

To: taapas1128, #hg-reviewers, martinvonz
Cc: martinvonz, pulkit, mercurial-devel