Summary:
Currently, adding a new workflow requires you to override ArcanistConfiguration, which is messy. Instead, just load everything that extends ArcanistBaseWorkflow.
Remove all the rules tying workflow names to class names through arcane incantations.
This has a very small performance cost in that we need to load every Workflow class every time now, but we don't hit __init__ and such anymore and it was pretty negligible on my machine (98ms vs 104ms or something).
Test Plan: Ran "arc help", "arc which", "arc diff", etc.
Reviewers: edward, vrana, btrahan
Reviewed By: edward
CC: aran, zeeg
Differential Revision: https://secure.phabricator.com/D3691
Summary: Allow the default to be set in global config, not just project config.
Test Plan: `arc set-config arc.land.onto.default derp; arc land`
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Differential Revision: https://secure.phabricator.com/D2686