- `tmp_dir` descends from Path
- convenient template methods to generate files and dirs, add them to
dvc and git and commit to git
- independent of old basic_env structures
- can go in any order
- modular: start with empty `tmp_dir`, initialize git with `scm`, dvc
repo with `dvc` add "repo template" with `repo_template`, ...
* dvc: fix branch suffixes in status/push/pull
* gc: add --all-commits flag
* gc: fix gc warning
Say that we always leave things used in the working tree