* gdrive: fix multi-remote workflow, cont. cleanup (3686) shcheklein
* setup: relax python-dateutil pip version constraint to include v2.8.2. 3701 (3702) dchichkov
* tag: getting rid of it (3699) skshetry
* remote.ssh: suppress paramiko logging (3675) pmrowla
* dvc: implement params support for pipeline file (3694) skshetry
* refactor: dvc/output class names unification (3695) nik123
* repo: use reverse post-order DFS in repro --downstream (3689) pmrowla
* remote: use string paths over PathInfo for performance reasons (3672) pmrowla
* dvc: implement multistage dvcfile (3676) skshetry
* refactor: dvc/dependency class names unification (3688) nik123
* refactor: dvc/remotes class names unification (3684) nik123
* progress: add main bars (3594) casperdcl
* git: is_tracked: use ls_files instead of walking the index (3677) efiop
* flake8: fix ambiguous var names (3674) pmrowla
* Convert all paths in config to posix-style (3665) charlesbaynham
* output: use strings instead of PathInfo for performance reasons (3663) pmrowla
* metrics: rework metrics implementation (3658) efiop
* Fix repro duplicating effort while checking steps 3644 (3645) charlesbaynham
* metrics diff error message in --no-scm projects (3650) karajan1001
* gc: don't forget to load remote index (3660) efiop
* remote: locally index list of checksums available on cloud remotes (3634) pmrowla
* refactor: extract stage loading outside of dvcfile (3655) skshetry
* tests: test_directories (3649) nik123
* Specify cmd arg names (metavars), et al. (3626) jorgeorpinel
* scm: git: clone: add progress (3595) casperdcl
* dvc: implement multi-stage dvcfile (3584) skshetry
* tests: add some DvcTree unit tests (3640) efiop
* dvc: introduce DvcTree (3639) efiop
* remote: don't use PathInfo.from_posix (3637) efiop
* remote config validation (3628) karajan1001
* params: diff: introduce --all (3631) efiop
* remote: use .dir checksum existence to infer file contents existence (3632) pmrowla
* refactor: extract stage's relationship with Dvcfile out from Stage (3619) skshetry
* Updates latest version of PyDrive2 (3624) mribeirodantas
* stage: resolve stage path before creating the stage (3630) efiop
* run: remove deprecated --cwd (3623) efiop