rhg: Parse system and user configuration at program start
… and pass it around up to `Repo::find`
Differential Revision: https://phab.mercurial-scm.org/D9962
== New Features ==
* `hg purge` is now a core command using `--confirm` by default.
* The `rev-branch-cache` is now updated incrementally whenever changesets
are added.
== New Experimental Features ==
* `hg diff` now takes an experimental `--merge` flag which causes `hg
diff --change` to show the changes relative to an automerge for
merge changesets. This makes it easier to detect and review manual
changes performed in merge changesets.
== Bug Fixes ==
== Backwards Compatibility Changes ==
== Internal API Changes ==
* `changelog.branchinfo` is deprecated and will be removed after 5.8.
It is superseded by `changelogrevision.branchinfo`.