Cover the new flag surface end to end against a real GitHub repo:
issue type set/remove on create and edit, parent set/remove on create
and edit, sub-issue add/remove (including the silent take-over of an
existing parent), blocked-by/blocking add/remove on create and edit,
list filtering by type, and the new non-tty view fields. Live in a
dedicated TestIssues2_0 suite so they're easy to run in isolation.
4e975fe4aa