tests/test-backwards-remove.t

phabricator: allow specifying reviewers on phabsend

Sometimes people want to specify reviewer explicitly for a stack. The
webpage only allows changing reviewer for one revision at a time. This patch
adds a `--reviewer` flag to make it easier to specify reviewers.

Test Plan:
On a test Phabricator instance, enable `differential.allow-self-accept`,
assign myself as a reviewer and make sure it works. Also try an invalid
username and make sure it raises.

Differential Revision: https://phab.mercurial-scm.org/D38

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ ls
  a
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

B should disappear

  $ ls
  a